The share prices of various AI-related companies have soared in this past year. Recently, however, they have fallen – in some cases dramatically. Is this a classic case of a bubble that is bursting, or at least deflating?
Take the case of NVIDIA, the world’s most valuable company, with a market capitalisation of around $4.2 trillion (at current share prices). It designs and produces graphics cards and is a major player in AI. From a low of $86.62 April this year, its share price rose to a peak of $212.19 on 29 October. But then began falling as talk grew of an AI bubble. Despite news on 19 November that its 2025 Q3 earnings were up 62% to $57.0bn, beating estimates by 4%, its share price, after a temporary rise, began falling again. By 21 November, it was trading at around $180.
Other AI-related stocks have seen much bigger rises and falls. One of the biggest requirements for an AI revolution is data processing, which uses huge amounts of electricity. Massive data centres are being set up around the world. Several AI-related companies have been building such data centres. Some were initially focused largely on ‘mining’ bitcoin and other cryptocurrencies (see the blog, Trump and the market for crypto). But many are now changing focus to providing processing power for AI.
Take the case of the Canadian company, Bitfarms Ltd. As it says on its site: ‘With access to multiple energy sources and strategic locations, our U.S. data centers support both mining and high-performance computing growth opportunities’. Bitfarms’ share price was around CAD1.78 in early August this year. By 15 October, it had reached CAD9.27 – a 421% increase. It then began falling and by 24 November was CAD3.42 – a decline of over 63%.
Data centres do have huge profit potential as the demand for AI increases. Many analysts are arguing that the current share price of data centres undervalues their potential. But current profits of such companies are still relatively low, or they are currently loss making. This then raises the question of how much the demand for shares, and hence their price, depends on current profits or future potential. And a lot here depends on sentiment.
If people are optimistic, they will buy and this will lead to speculation that drives up the share price. If sentiment then turns and people believe that the share price is overvalued, with future profits too uncertain or less than previously thought, or if they simply believe that the share price has overshot the value that reflects a realistic profit potential, they will sell and this will lead to speculation that drives down the share price
The dot.com bubble of the late 1990s/early 2000s is a case in point. There was a stock market bubble from roughly 1995 to 2001, where speculative investment in internet-based companies caused their stock values to surge, peaking in late 1999/early 2000. There was then a dramatic crash. But then years later, many of these companies’ share prices had risen well above their peak in 2000.
Take the case of Amazon. In June 1997, its share price was $0.08. By mid-December 1999, it had reached $5.65. It then fell, bottoming out at $0.30 in September 2001. The dot-com bubble had burst.
But the potential foreseen in many of these new internet companies was not wrong. After 2001, Amazon’s share price began rising once more. Today, Amazon’s shares are trading at over $200 – the precise value again being driven largely by the company’s performance and potential and by sentiment.
So is the boom in AI-related stock a bubble? Given that the demand for AI is likely to continue growing rapidly, it is likely that the share price of companies providing components and infrastructure for AI is likely to continue growing in the long term. But just how far their share prices will fall in the short term is hard to call. Sentiment is a fickle thing.
Articles
Questions
- Using a supply and demand diagram, illustrate how speculation can drive up the share price of a company and then result in it falling.
- What is meant by overshooting in a market? What is the role of speculation in this process?
- Does a rapid rise in the price of an asset always indicate a bubble? Explain.
- What are the arguments for suggesting that markets are/are not experiencing an AI share price bubble? Does it depend of what part of the AI market is being considered?
- What is meant by the market capitalisation of a company? Is it a good basis for deciding whether or not a company’s share price is a true reflection of the company’s worth? What other information would you require?
- Find out what has been happening to the price of Bitcoin. What factors determine the price of Bitcoin? Do these factors make the price inherently unstable?
The UK’s poor record on productivity since the 2008 financial crisis is well documented, not least in this blog series. Output per worker has flatlined over the 17 years since the crisis. As was noted in the blog, The UK’s poor productivity record, low UK productivity is caused by a number of factors, including the lack of investment in training, the poor motivation of many workers and the feeling of being overworked, short-termism among politicians and management, and generally poor management practices.
One of the most significant issues identified by analysts and commentators is the lack of investment in physical capital, both by private companies and by the government in infrastructure. Gross fixed capital formation (a measure of investment) has been much lower in the UK compared to international competitors.
From Figure 1 it can be observed that, since the mid-1990s, the UK has consistently had lower investment as a percentage of GDP compared to other significant developed market economies. The cumulative effect of this gap has contributed to lower productivity and lower economic growth.
Interestingly, since the financial crisis, UK firms have had high profitability and associated high cash holdings. This suggests that firms have had a lot of financial resources to reinvest. However, data from the OECD suggests that reinvestment rates in the UK, typically 40–50% of profit, are much lower than in many other OECD countries. In the USA the rate is 50%, in Germany 60–70% and in Japan 70%+. There is much greater emphasis in the UK on returning funds to shareholders through dividends and share buybacks. However, the reinvestment of much of this cash within firms could have gone some way to addressing the UK’s investment gap – but, it hasn’t been done.
Analysis by the OECD suggest that, while the cost of financing investment has declined since the financial crisis, the gap between this and the hurdle rate used to appraise investments has widened. Between 2010 and 2021 the difference nearly doubled to 4%. This increase in the hurdle rate can be related to increases in the expected rate of return by UK companies and their investors.
In this blog we will analyse (re)investment decisions by firms, discussing how increases in the expected rate of return in the UK raise the hurdle rate used to appraise investments. This reduces the incentive to engage in long-term investment. We also discuss policy prescriptions to improve reinvestment rates in the UK.
Investment and the expected rate of return
Investment involves the commitment of funds today to reap rewards in the future. This includes spending on tangible and intangible resources to improve the productive capacity of firms. Firms must decide whether the commitment of funds is worthwhile. To do so, economic theory suggests that they need to consider the compensation required by their provider of finance – namely, investors.
What rewards do investors require to keep their funds invested with the firm?
When conducting investment appraisal, firms compare the estimated rate of return from an investment with the minimum return investors are prepared to receive (termed the ‘expected return’). Normally this is expressed as a percentage of the initial outlay. Firms have to offer returns to investors which are equal to or greater than the minimum expected return – the return that is sufficient to keep funds invested in the firm. Therefore, returns above this minimum expected level are termed ‘excess returns’.
When firms conduct appraisals of potential investments, be it in tangible or intangible capital, they need to take into account the fact that net benefits, expressed as cash flows, will accrue over the life of the investment, not all at once. To do this, they use discounted cash flow (DCF) analysis. This converts future values of the net benefits to their present value. This is expressed as follows:

Where:
NPV = Net present value (discounted net cash flows);
K = Capital outlay (incurred at the present time);
C = Net cash flows (occur through the life of the investment project);
r = Minimum expected rate of return.
In this scenario, the investment involves an initial cash outlay (K), followed in subsequent periods by net cash inflows each period over the life of the investment, which in this case is 25 years. All the cash flows are discounted back to the present so that they can be compared at the same point in time.
The discount rate (r) used in appraisals to determine the present value of net cash flows is determined by the minimum expected return demanded by investors. If at that hurdle rate there are positive net cash flows (+NPV), the investment is worthwhile and should be pursued. Conversely, if at that hurdle rate there are negative net cash flows (–NPV), the investment is not worthwhile and should not be pursued.
According to economic theory, if a firm cannot find any investment projects that produce a positive NPV, and therefore satisfy the minimum expected return, it should return funds to shareholders through dividends or share buybacks so that they can invest the finance more productively.
Firm-level data from the OECD suggest that UK firms have had higher profits and this has been associated with increased cash holdings. But, due to the higher hurdle rate, less investment is perceived to be viable and thus firms distribute more of their profits through dividends and share buybacks. These payouts represent lost potential investment and cumulatively produce a significant dent in the potential output of the UK economy.
Why are expected rates of return higher in the UK?
This higher minimum rate of expected return can be explained by factors influencing its determinants; opportunity cost and risk/uncertainty.
Higher opportunity cost. Opportunity cost relates to the rate of return offered by alternatives. Investors and, by implication firms, will have to consider the rate of return offered by alternative investment opportunities. Typically, investors have focused on interest rates as a measure of opportunity cost. Higher interest rates raise the opportunity cost of an investment and increase the minimum expected rate of return (and vice versa with lower interest rates).
However, it is not interest rates that have increased the opportunity cost, and hence the minimum expected rate of return associated with investment, in the UK since the financial crisis. For most of the period since 2008, interest rates have been extremely low, sitting at below 1%, only rising significantly during the post-pandemic inflationary surge in 2022. This indicates that this source of opportunity cost for the commitment of business investment has been extremely low.
However, there may be alternative sources of opportunity cost which are pushing up the expected rate of return. UK investors are not restricted to investing in the UK and can move their funds between international markets determined by the rate of return offered. The following table illustrates the returns (in terms of percentage stock market index gain) from investing in a sample of UK, US, French and German stock markets between August 2010 and August 2025.

When expressed in sterling, returns offered by UK-listed companies are lower across the whole period and in most of the five-yearly sub-periods. Indeed, the annual equivalent rate of return (AER) for the FTSE 100 index across the whole period is less than half that of the S&P 500. The index offered a paltry annual return of 2.57% between 2015 and 2020, while the US index offered a return of 16.48%. Both the French and German indices offered higher rates of return, in the latter part of the period particularly. This represents a higher opportunity cost for UK investors and may have increased their expectations about the return they require for UK investments.
Greater perceived risk/uncertainty. Expected rates of return are also determined by perceptions of risk and uncertainty – the compensation investors need to bear the perceived risk associated with an investment. Investors are risk averse. They demand higher expected return as compensation for higher perceived risk. Higher levels of risk aversion increase the expected rate of return and related investment hurdle rates.
There has been much discussion of increased uncertainty and risk aversion among global investors and firms (see the blogs Rising global uncertainty and its effects, World Uncertainty Index, The Chancellor’s fiscal dilemma and Investment set to fall as business is baffled by Trump). The COVID-19 pandemic, inflation shocks, the war in Ukraine, events across the Middle East and the trade policies adopted by the USA in 2025 have combined to produce a very uncertain business environment.
While these have been relatively recent factors influencing world-wide business uncertainty, perceptions of risk and uncertainty concerning the UK economy seem to be longer established. To measure policy-related economic uncertainty in the UK, Baker, Bloom and Davis at www.PolicyUncertainty.com construct an index based on the content analysis of newspaper articles mentioning terms reflecting policy uncertainty.
Figure 2 illustrates the monthly index from 1998 to July 2025. The series is normalised to standard deviation 1 prior to 2011 and then summed across papers, by month. Then, the series is normalised to mean 100 prior to 2011.
Some of the notable spikes in uncertainty in the UK since 2008 have been labelled. Beginning with the global financial crisis, investors and firms became much more uncertain. This was exacerbated by a series of economic shocks that hit the economy, one of which, the narrow vote to leave the European Union in 2016, was specific to the UK. This led to political turmoil and protracted negotiations over the terms of the trade deal after the UK left. This uncertainty has been exacerbated recently by the series of global shocks highlighted above and also the budget uncertainty of Liz Truss’s short-lived premiership and now the growing pressure to reduce government borrowing.
While spikes in uncertainty occurred before the financial crises, the average level of uncertainty, as measured by the index, has been much higher since the crisis. From 1998 to 2008, the average value was 89. Since 2008, the average value has been 163. Since the Brexit vote, the average value has been 185. This indicates a much higher perception of risk and uncertainty over the past 15 year and this translates into higher minimum expected return as compensation. Consequently, this makes many long-term investment projects less viable because of higher hurdle rates. This produces less productive investment in capital, contributing significantly to lower productivity.
Policy proposals
There has been much debate in the UK about promoting greater long-term investment. Reforms have been proposed to improve public participation in long-term investment through the stock market. To boost investment, this would require the investing public to be prepared to accept lower expected returns for a given level of risk or accept higher risk for a given level of returns.
Evidence suggests that the appetite for this may be very low. UK savers tend to favour less risky and more liquid cash deposits. It may be difficult to encourage them to accept higher levels of risk. In any case, even if they did, many may invest outside the UK where the risk-return trade-off is more favourable.
Over the past 10 years, policy uncertainty has played a significant role in deterring investment. So, if there is greater continuity, this may then promote higher levels of investment.
The Labour government has proposed policies which aim to share or reduce the risk/uncertainty around long-term investment for UK businesses. For instance, a National Wealth Fund (NWF) has been established to finance strategic investment in areas such as clean energy, gigafactories and carbon capture. Unfortunately, the Fund is financed by borrowing through financial markets and the amount expected to be committed over the life of the current Parliament is only £29 billion, assuming that private capital matches public commitments in the ratio expected. It is questionable whether the Fund’s commitment will be sufficient to attract private capital.
Alternatively, Invest 2035 is a proposal to create a stable, long-term policy environment for business investment. It aims to establish an Industrial Strategy Council for policy continuity and to tackle issues like improving infrastructure, reducing energy costs and addressing skills gaps. Unfortunately, even if there is some attempt at domestic policy stability, the benefits may be more than offset by perceptions around global uncertainty, which may mean that UK investors’ minimum expected rates of return remain high and long-term investment low for the foreseeable future.
Articles
Data
Questions
- Use the marginal efficiency of capital framework to illustrate the ‘lost’ investment spending in the UK due to the investment hurdle rate being higher than the cost of capital.
- Explain the arbitrage process which produces the differences in valuations of UK securities and foreign ones due to differences in the expected rate of return.
- Sketch an indifference curve for a risk-averse investor, treating expected return and risk as two characteristics of a financial instrument.
- How does higher uncertainty affect the slope of an indifference curve for such an investor? How does this affect their investment hurdle rate?
- Analyse the extent to which the proposed polices can reduce the investment hurdle rate for UK companies and encourage greater levels of investment.
In a blog in October 2024, we looked at global uncertainty and how it can be captured in a World Uncertainty Index. The blog stated that ‘We continue to live through incredibly turbulent times. In the past decade or so we have experienced a global financial crisis, a global health emergency, seen the UK’s departure from the European Union, and witnessed increasing levels of geopolitical tension and conflict’.
Since then, Donald Trump has been elected for a second term and has introduced sweeping tariffs. What is more, the tariffs announced on so-called ‘Liberation Day‘ have not remained fixed, but have fluctuated with negotiations and threatened retaliation. The resulting uncertainty makes it very hard for businesses to plan and many have been unwilling to commit to investment decisions. The uncertainty has been compounded by geopolitical events, such as the continuing war in Ukraine, the war in Gaza and the June 13 Israeli attack on Iran.
The World Uncertainty Index (WUI) tracks uncertainty around the world by applying a form of text mining known as ‘term frequency’ to the country reports produced by the Economist Intelligence Unit (EIU). The words searched for are ‘uncertain’, ‘uncertainty’ and ‘uncertainties’ and the number of times they occur as percentage of the total words is recorded. To produce the WUI this figure is then multiplied by 1m. A higher WUI number indicates a greater level of uncertainty.
The monthly global average WUI is shown in Chart 1 (click here for a PowerPoint). It is based on 71 countries. Since 2008 the WUI has averaged a little over 23 000: i.e. 2.3 per cent of the text in EIU reports contains the word ‘uncertainty’ or a close variant. In May 2025, it was almost 79 000 – the highest since the index was first complied in 2008. The previous highest was in March 2020, at the start of the COVID-19 outbreak, when the index rose to just over 56 000.
The second chart shows the World Trade Uncertainty Index (WTUI), published on the same site as the WUI (click here for a PowerPoint). The method adopted in its construction therefore mirrors that for the WUI but counts the number of times in EIU country reports ‘uncertainty’ is mentioned within proximity to a word related to trade, such as ‘protectionism’, ‘NAFTA’, ‘tariff’, ‘trade’, ‘UNCTAD’ or ‘WTO.’
The chart shows that in May 2025, the WTUI had risen to just over 23 000 – the second highest since December 2019, when President Trump imposed a new round of tariffs on Chinese imports and announced that he would restore steel tariffs on Brazil and Argentina. Since 2008, the WTUI has averaged just 2228.
It remains to be seen whether more stability in trade relations and geopolitics will allow WUI and WUTI to decline once more, or whether greater instability will simply lead to greater uncertainty, with damaging consequences for investment and also for consumption and employment.
Articles
- IMF World Economic Outlook: economic uncertainty is now higher than it ever was during COVID
The Conversation, Sergi Basco (23/4/25)
- Economic uncertainty hits new high
McKinsey, Sven Smit et al. (29/5/25)
- Trade tensions and rising uncertainty drag global economy towards recession
UNCTAD News (25/4/25)
- IMF Warns Global Economic Uncertainty Surpasses Pandemic Levels
The Global Treasurer (24/4/25)
- Britons ‘hoarding cash amid economic uncertainty and fear of outages’
The Guardian, Phillip Inman (10/6/25)
- America’s Brexit Phase
Foreign Affairs, Jonathan Haskel and Matthew J. Slaughter (10/6/25)
- Goldman Sachs’ CEO on the ‘Big, Beautiful Bill,’ Trump’s Tariffs and Economic Volatility
Politico, Sam Sutton (13/6/25)
- The Countries Where Economic Uncertainty Is Rising Fastest
24/7 Wall St., Evan Comen (9/6/25)
- Trump’s tariffs have finally kicked in, so what happens next?
The Conversation, Maha Rafi Atal (8/8/25)
Uncertainty Indices
Questions
- Explain what is meant by ‘text mining’. What are its strengths and weaknesses in assessing business, consumer and trade uncertainty?
- Explain how the UK Monthly EPU Index is derived.
- Why has uncertainty increased so dramatically since the start of 2025?
- Compare indices based on text mining with confidence indices.
- Plot consumer and business/industry confidence indicators for the past 24 months, using EC data. Do they correspond with the WUI?
- How may uncertainty affect consumers’ decisions?
For a while now, debate has raged over how to revive the fortunes of the London Stock Exchange (LSE). Since the 2008 financial crisis, the market has suffered a lack of investment, poor liquidity and low performance. This has produced a moribund financial market which has become unattractive to both investors and companies. Returns from the UK market lag international competitors, particularly the USA (see the chart).

Investment in the S&P 500 Index over the period would have produced annualised rates of return of 14.35%, more than double that from the FTSE 100 Index. Part of this underperformance is due to the industrial mix of the listed companies: low-growth energy and mining compared to the high-growth technology sectors in the USA. This has led to the perception that London is not a place for firms to list, particularly those in high-growth sectors.
In 2024, 88 companies choose to delist or transfer their primary listing elsewhere. Only 18 took their place. Several big companies from a range of industries, including Ashtead, Flutter and CRH have transferred their primary listing to New York or have plans to do so.
The new Labour government views stimulating higher levels of investment though the London market as an important element in its drive to boost productivity and growth in the UK. Recently, it has been reported that investment institutions have been lobbying the UK government to reduce significantly the tax-free allowance for Cash Individual Savings Accounts (ISAs) as a way to encourage more of UK households’ savings to be channelled through the UK stock market.
Currently, UK savers can save up to £20 000 annually into ISAs without paying tax on the interest earned. This can be held solely in Cash ISAs, or in a combination of Cash plus Stocks and Shares ISAs. The tax-free instruments which were introduced by a Labour government in 1999 to encourage higher savings have proved immensely popular. Data from Paragon Bank indicate that over £350 billion are held in these accounts. However, under the new proposals, the amount which would be allowed to be saved as cash has been rumoured to be cut to £4000 per year, with the hope that some of it will be invested in the UK stock market.
The proposals have proved controversial, with high-profile figures voicing opposition. In this blog, we’ll analyse the reasons behind the proposal and discuss whether it will have the desired effect of stimulating higher levels of investment. We’ll also discuss other proposed policies for making the LSE a more effective channel for investment flows to boost economic growth.
Stock markets and the saving and investment channel
The main reason for the proposed ISA change is to encourage more investment in the UK stock market. By reducing the amount which can be saved in Cash ISAs, the government hopes to encourage savers to invest in Stocks and Shares ISAs instead, particularly ones linked to the UK market. This would increase the amount of finance capital in the market, thereby boosting its liquidity. This would then make it an attractive place for young, vibrant UK and foreign companies to list.
An active, liquid secondary market in shares is important to attract firms to list on stock exchanges by issuing shares to outside investors. Traditionally, this channel has been important to the growth and development of firms.
Existing savings in Cash ISAs are deposited with financial institutions such as banks and building societies. Through the credit-creation process such funds can be used to finance productive investment. In countries like the UK, lending by financial institutions is an important way that investment is financed, particularly for small and medium-sized enterprises. However, scale limits, regulatory restrictions and the need to diversify lending properly means that there are limits to the financing available for company investment through these institutions.
Capital markets like the LSE are intended to meet these larger-scale requirements. Financial claims, such as debt and equity, are divided into atomised instruments and sold to outside investors to fund investment and business growth.
Further, the desire for a capital injection to finance growth is not the only reason that firms seek stock market listings. Founders of companies may have a lot of wealth invested in the equity of their firms. Selling some of their equity to outside investors through a stock market listing is a way of diversifying their wealth. However, if they are to maximise the potential sale price, there must be an active, liquid secondary market to encourage investors to buy shares in the primary market.
Proponents of reform want to encourage a greater appetite for risk among UK investors, which will produce more savings being channelled through the LSE.
One issue is whether savers will respond in the way anticipated and channel more funds through the UK stock market. Many savers like the security of Cash ISAs. Such vehicles offer a low-risk/low-return combination, which savers like because the tax benefits boost returns. A survey by the Nottingham Building Society found that a substantial number of Cash ISA savers are concerned that the proposed changes could affect their ability to save for important financial goals, such as buying a house or building an emergency fund. Higher-risk Stocks and Shares ISAs are not suitable for such savings because of the potential to lose the initial amount invested. Many may not be prepared to do so and one-third suggested they would save less overall.
According to the survey, only 38% of Cash ISA holders said they would consider investing in Stocks and Shares ISAs if the Cash ISA allowance were reduced. It may be difficult to alter such risk-averse preferences given the average amount saved through ISAs and demographics. In 2022/23, the average amount subscribed to ISAs was £5000. This does not suggest that average households have a significant surplus of cash that they may want to investment at a high risk through the stock market. Indeed, many may want to have access to the cash at short notice and so are not prepared to forgo liquidity for the time needed to accrue the benefits of compounding which stock market investing produces.
Demographics may also play a role in this. Many of those who save more are now retired, or near retirement. They are less likely to see the appeal of compounding returns over long periods through investment in shares. Instead, with shorter investment horizons, they may only see the potential for losses associated with Stocks and Shares ISAs. Indeed, they will be starting to liquidate their long-term positions to draw income in retirement. Therefore, they may save less.
For others, who may be prepared to accept the additional risk, with the prospect of higher returns in the way that advocates of the reform hope for, the reduction in the Cash ISA allowance does not necessarily mean that they will invest in Stocks and Shares ISAs linked to the UK market. Since returns from the UK market have lagged international competitors, it may be that savers will channel their savings to those international markets, particularly in the USA, where the risk–return relationship has been more rewarding. Doing so has been made much easier and cheaper through a combination of economic forces including technological advances, regulatory changes and increased competition. This makes it much easier for UK savers to channel investment funds to wherever potential return is highest. At the moment, this is unlikely to be the UK, meaning that the anticipated boost to investment funds may not be as much as anticipated.
Critics of the proposal also question the motives of investment fund managers who have been lobbying government. They argue that the reforms will mean that many people who do now choose to save in Stocks and Shares ISAs will buy funds managed by fund managers who will receive fees for doing so. Critics argue that it is the prospect of higher fees which is the real motive behind the lobbying, not any desire to boost investment and growth.
What alternatives are available to boost the London Stock Exchange
The low valuations of LSE-listed companies compared to their international counterparts, particularly those in the USA, has discouraged growing firms from listing in London. To address this, there have been calls to enhance corporate governance standards and reduce regulatory burdens for listed companies.
This has already been recognised by the authorities. In 2024, UK regulators approved the biggest overhaul of rules regulating London-listed companies. The new listing rules will hand more power to company bosses to make decisions without shareholder votes. They will give companies more flexibility to adopt dual-class share structures used by founders and venture capital firms to give themselves stronger voting rights than other investors. This is particularly popular for founders who want to diversify their wealth without sacrificing control and is used frequently by tech companies and venture capitalists when listing in the USA. Such reforms may attract more companies in high-growth sectors to list in London.
Tax policies which provide the right incentives to buy and sell shares could also encourage more investment in the LSE. For instance, the repeal in the mid-1990s of the preferential tax treatment of dividend income for UK pension funds and insurance companies is seen as a major factor in discouraging those institutions from investing more funds in the London market. Since tax on capital gains is only liable when they are realised, this reduces their present value versus the equivalent amount on dividends.
As the following table illustrates, given the significantly higher percentage of total returns derived from dividends in the LSE compared to other exchanges, the equal tax treatment of dividend and capital gains provides an incentive to seek jurisdictions where capital gains predominate. This is what UK pension funds have done. Data from the Office of National Statistics show that in 2024, 77% of UK occupational pensions equity investments were overseas.

Reinstating this tax benefit could stimulate greater demand for UK equity from this significant sector, boosting liquidity in the London market. Allied to this are proposals from the UK government to consolidate the fragmented UK pension industry to achieve greater scale economies in that channel for investment. This can reduce financing costs, boosting the marginal return from UK investments for these funds, encouraging greater investment in the UK market (ceteris paribus).
Further, the 2.5% stamp duty on share purchases has been viewed as another disincentive for both retail and institutional investors to engage in security trading on the London Stock Exchange. The duty, which is much higher than in peer economies, effectively raises the expected rate of return on UK equites which depresses perceptions of their values and prices. Its removal may raise trading volumes, improving the liquidity of the market and be offset by increased tax revenues in the future. However, the Treasury suggests that the removal of stamp duty is doubtful, since it would create a significant hole in the UK government’s budget.
Ultimately, many of these reforms may have limited impact on investment. Efforts to boost confidence in the stock market will depend on improving the overall economic environment in the UK. Therefore, it will be the wider policies promoting growth in general which will increase the rates of return offered by London-listed firms and be more significant to attracting capital to London.
However, many of these are controversial themselves, such as relaxing laws around planning permissions and addressing business uncertainties around post-Brexit trading arrangements with the European Union. These broader economic measures could help make the UK generally, and the LSE specifically, more appealing to both domestic and international investors.
Conclusion
The UK government’s proposal to reduce the Cash ISA allowance is part of a broader strategy to boost investment in the stock market and stimulate economic growth. While this change could lead to more capital being directed towards productive investments, it also poses challenges for savers who like the security and simplicity of Cash ISAs.
The ultimate impact will depend on how savers respond to these changes. The potential reduction in overall savings rates could counteract some of the intended benefits. Further, the extent to which they are prepared to channel their savings into UK-listed companies will be important. If many seek higher returns elsewhere, the impact on the UK stock market may be limited. In any case, policies to address the problems of the UK stock market will only work if the wider issues associated with UK productivity and growth are addressed.
Articles
Data
Questions
- Explain how banks use cash ISAs to finance investment through credit creation.
- What do stock markets offer which may boost investment and economic growth?
- What are the issues with the London Stock Exchange which is making it unattractive for raising finance?
- How is the rumoured ISA reform intended to help address these issues?
- Analyse the extent to which it will do so.
- How might some of the broader reforms proposed by the UK government influence rate of return on UK equities and attract capital?
We continue to live through incredibly turbulent times. In the past decade or so we have experienced a global financial crisis, a global health emergency, seen the UK’s departure from the European Union, and witnessed increasing levels of geopolitical tension and conflict. Add to this the effects from the climate emergency and it easy to see why the issue of economic uncertainty is so important when thinking about a country’s economic prospects.
In this blog we consider how we can capture this uncertainty through a World Uncertainty Index and the ways by which economic uncertainty impacts on the macroeconomic environment.
World Uncertainty Index
Hites Ahir, Nicholas Bloom and Davide Furceri have constructed a measure of uncertainty known as the World Uncertainty Index (WUI). This tracks uncertainty around the world using the process of ‘text mining’ the country reports produced by the Economist Intelligence Unit. The words searched for are ‘uncertain’, ‘uncertainty’ and ‘uncertainties’ and a tally is recorded based on the number of times they occur per 1000 words of text. To produce the index this figure is then multiplied up by 100 000. A higher number therefore indicates a greater level of uncertainty. For more information on the construction of the index see the 2022 article by Ahir, Bloom and Furceri linked below.
Figure 1 (click here for a PowerPoint) shows the WUI both globally and in the UK quarterly since 1991. The global index covers 143 countries and is presented as both a simple average and a GDP weighted average. The UK WUI is also shown. This is a three-quarter weighted average, the authors’ preferred measure for individual countries, where increasing weights of 0.1, 0.3 and 0.6 are used for the three most recent quarters.
From Figure 1 we can see how the level of uncertainty has been particularly volatile over the past decade or more. Events such as the sovereign debt crisis in parts of Europe in the early 2010s, the Brexit referendum in 2016, the COVID-pandemic in 2020–21 and the invasion of Ukraine in 2022 all played their part in affecting uncertainty domestically and internationally.
Uncertainty, risk-aversion and aggregate demand
Now the question turns to how uncertainty affects economies. One way of addressing this is to think about ways in which uncertainty affects the choices that people and businesses make. In doing so, we could think about the impact of uncertainty on components of aggregate demand, such as household consumption and investment, or capital expenditures by firms.
As Figure 2 shows (click here for a PowerPoint), investment is particularly volatile, and much more so than household spending. Some of this can be attributed to the ‘lumpiness’ of investment decisions since these expenditures tend to be characterised by indivisibility and irreversibility. This means that they are often relatively costly to finance and are ‘all or nothing’ decisions. In the context of uncertainty, it can make sense therefore for firms to wait for news that makes the future clearer. In this sense, we can think of uncertainty rather like a fog that firms are peering through. The thicker the fog, the more uncertain the future and the more cautious firms are likely to be.
The greater caution that many firms are likely to adopt in more uncertain times is consistent with the property of risk-aversion that we often attribute to a range of economic agents. When applied to household spending decisions, risk-aversion is often used to explain why households are willing to hold a buffer stock of savings to self-insure against unforeseen events and their future financial outcomes being worse than expected. Hence, in more uncertain times households are likely to want to increase this buffer further.
The theory of buffer-stock saving was popularised by Christopher Carroll in 1992 (see link below). It implies that in the presence of uncertainty, people are prepared to consume less today in order to increase levels of saving, pay off existing debts, or borrow less relative to that in the absence of uncertainty. The extent of the buffer of financial wealth that people want to hold will depend on their own appetite for risk, the level of uncertainty, and the moderating effect from their own impatience and, hence, present bias for consuming today.
Risk aversion is consistent with the property of diminishing marginal utility of income or consumption. In other words, as people’s total spending volumes increase, their levels of utility or satisfaction increase but at an increasingly slower rate. It is this which explains why individuals are willing to engage with the financial system to reallocate their expected life-time earnings and have a smoother consumption profile than would otherwise be the case from their fluctuating incomes.
Yet diminishing marginal utility not only explains consumption smoothing, but also why people are willing to engage with the financial system to have financial buffers as self-insurance. It explains why people save more or borrow less today than suggested by our base-line consumption smoothing model. It is the result of people’s greater dislike (and loss of utility) from their financial affairs being worse than expected than their like (and additional utility) from them being better than expected. This tendency is only likely to increase the more uncertain times are. The result is that uncertainty tends to lower household consumption with perhaps ‘big-ticket items’, such as cars, furniture, and expensive electronic goods, being particularly sensitive to uncertainty.
Uncertainty and confidence
Uncertainty does not just affect risk; it also affects confidence. Risk and confidence are often considered together, not least because their effects in generating and transmitting shocks can be difficult to disentangle.
We can think of confidence as capturing our mood or sentiment, particularly with respect to future economic developments. Figure 3 plots the Uncertainty Index for the UK alongside the OECD’s composite consumer and business confidence indicators. Values above 100 for the confidence indicators indicate greater confidence about the future economic situation and near-term business environment, while values below 100 indicate pessimism towards the future economic and business environments.
Figure 3 suggests that the relationship between confidence and uncertainty is rather more complex than perhaps is generally understood (click here for a PowerPoint). Haddow, Hare, Hooley and Shakir (see link below) argue that the evidence tends to point to changes in uncertainty affecting confidence, but with less evidence that changes in confidence affect uncertainty.
To illustrate this, consider the global financial crisis of the late 2000s. The argument can be made that the heightened uncertainty about future prospects for households and businesses helped to erode their confidence in the future. The result was that people and businesses revised down their expectations of the future (pessimism). However, although people were more pessimistic about the future, this was more likely to have been the result of uncertainty rather than the cause of further uncertainty.
Conclusion
For economists and policymakers alike, indicators of uncertainty, such as the Ahir, Bloom and Furceri World Uncertainty Index, are invaluable tools in understanding and forecasting behaviour and the likely economic outcomes that follow. Some uncertainty is inevitable, but the persistence of greater uncertainty since the global financial crisis of the late 2000s compares quite starkly with the relatively lower and more stable levels of uncertainty seen from the mid-1990s up to the crisis. Hence the recent frequency and size of changes in uncertainty show how important it to understand how uncertainty effects transmit through economies.
Academic papers
- The World Uncertainty Index
National Bureau of Economic Research, Working Paper 29763, Hites Ahir, Nicholas Bloom and Davide Furceri (February 2022)
- The Buffer-Stock Theory of Saving: Some Macroeconomic Evidence
Brookings Papers on Economic Activity, Christopher D Carroll (Vol 2, 1992)
- Macroeconomic uncertainty: what is it, how can we measure it and why does it matter?
Bank of England Quarterly Bulletin, 2013 Q2, Abigail Haddow, Chris Hare, John Hooley and Tamarah Shakir (13/6/13)
Articles
Data
Questions
- (a) Explain what is meant by the concept of diminishing marginal utility of consumption.
(b) Explain how this concept helps us to understand both consumption smoothing and the motivation to engage in buffer-stock saving.
- Explain the distinction between confidence and uncertainty when analysing macroeconomic shocks.
- Discuss which types of expenditures you think are likely to be most susceptible to uncertainty shocks.
- Discuss how economic uncertainty might affect productivity and the growth of potential output.
- How might the interconnectedness of economies affect the transmission of uncertainty effects through economies?