Top 10 best-selling ISA and SIPP funds in May

Temperatures hit record highs in May - and the stock market followed suit. The S&P 500 hit 11 new highs last month, helped by a lower oil price and bumper results from technology firms.

Elsewhere, the picture was a little less rosy. European stock markets lagged behind, and North America's gains masked a widening divide beneath the surface. The rally was driven almost entirely by AI stocks, while energy shares slumped. How did investors react?

Read on for the top 10 ISA and SIPP funds in May, or click below for the best-selling investment trusts and exchange traded funds (ETFs).

• Read: Top 10 best-selling investment trusts in May
• Read: Top 10 best-selling ETFs in May

Cash funds

Despite strong performances from the world’s biggest companies, personal investors were cautious in May. Lots of money flowed into cash funds, which sit at the lowest end of the investment risk spectrum.

Cash funds - also known as money market funds - roughly track UK interest rates. They invest in different forms of short-term debt, including government bonds. Crucially, the holdings are very high quality, liquid, and diversified. This means the funds themselves are liquid, stable and low risk - albeit slightly higher risk than a traditional savings account.

The Fidelity Cash Fund was a favourite, as was the Royal London Short Term Money Market Fund.

Persistently high interest rates have made cash funds much more appealing. The Bank of England held the base rate at 3.75% in April and traders think it could rise to 4% by the end of the year. This is the opposite of what markets predicted before conflict broke out in the Middle East.

• Read more: Where next for interest rates?

Investors may also be nervous about equity valuations - particularly in the US. North America represents about 70% of the global market and looks pricey by virtually every yardstick, thanks in large part to Big Tech.

• Read more: What are the world’s cheapest stock markets?

Past performance is not a reliable indicator of future returns

Source: Morningstar from 31.3.21 to 31.3.26. Basis bid to bid with income reinvested in GBP. Excludes initial charge.

AI giants

That said, ISA investors are still buying Big Tech. Polar Capital Global Technology is an actively managed fund that invests across the sector. It holds everything from semiconductor stocks to electrical equipment makers. Over 60% of the fund is invested in the US and Canada, but it also offers some hefty exposure to Asia Pacific.

Top holdings include giants like Nvidia, Alphabet and TSMC, but the 12-person investment team looks slightly further down the food chain as well. This has translated into remarkable growth over the past 12 months.

The Polar Capital Artificial Intelligence Fund also made it onto the ISA best-sellers list. This fund seeks out opportunities in automation, robotics, AI, and materials science - as well as companies that could be “fundamentally transformed” by these technologies. Nvidia is the biggest holding, but there are plenty of less familiar names too, including Japanese metals company Mitsui Mining & Smelting Co and Vertiv, a US group that provides infrastructure and services for data centres.

SIPP customers favoured the Legal & General Global Technology Index Trust. This is a passive fund that aims to track the performance of the FTSE World Technology Index. As such, it has lower fees but does not have fund managers shaping the portfolio.

Past performance is not a reliable indicator of future returns

Source: Morningstar from 31.3.21 to 31.3.26. Basis bid to bid with income reinvested in GBP. Excludes initial charge.

World trackers

World tracker funds were also popular last month, with Fidelity Index World Fund, Vanguard FTSE Global All Cap Index, Legal & General Global Equity Index Fund and HSBC FTSE All World Index all making it onto the best-sellers list.

These tracker funds let you invest in both developed and emerging markets for a relatively low fee. They also offer plenty of exposure to the tech sector, given that the ‘Magnificent 7’ represent about a fifth of the global market.

It is easy to think that all tracker funds are the same - but they’re not. The Vanguard fund is more diversified than many, offering exposure to developed and emerging markets. Its top 10 holdings represent just over a fifth of the total portfolio. In contrast, the Fidelity fund focuses exclusively on developed markets, and its top 10 holdings represent 27% of the total portfolio. The HSBC and L&G funds sit somewhere in between.

• Read: Which global index fund is best for you?

A big part of the appeal of all these funds, however, is their price. They allow you to ride the ups and downs of the global market for an ongoing charge of between 0.12% and 0.23%.

Past performance is not a reliable indicator of future returns

Source: Morningstar from 31.3.21 to 31.3.26. Basis bid to bid with income reinvested in GBP. Excludes initial charge.

Dividend giants

Personal investors are on the hunt for dividends too. The Fidelity Global Dividend Fund and Artemis Global Income Fund are consistently popular this year - although the former did slip out of the rankings in May.

Fidelity Global Dividend Fund is an actively managed fund that targets companies with healthy yields underpinned by rising income. The portfolio invests across a variety of sectors and geographies, offering a good level of diversification (the US represents less than a quarter of the portfolio). It also aims to deliver less volatility than the wider market, which may be attractive in today’s unpredictable world. 

The Artemis Global Income Fund has a different focus. It is heavily weighted towards the financial sector and has some chunky exposure to emerging markets. Like the Fidelity fund, however, it has limited its US holdings and is looking for generous dividend yields. Free cash flow is its key metric, and it has delivered explosive growth over the past 12 months. It has more of a macro mindset than many funds, assessing how things like inflation and interest rates will impact countries and sectors.

The fund also stands out for its focus on lesser-known companies. While familiar names like Samsung feature among its top holdings, others - such as Hanwha Aerospace - are less widely covered in the UK.

The fund has had a fantastic few years. While Fidelity Global Dividend aims to dampen volatility, however, Artemis Global Income’s performance has lurched around in the past.

Past performance is not a reliable indicator of future returns

Source: Morningstar from 31.3.21 to 31.3.26. Basis bid to bid with income reinvested in GBP. Excludes initial charge.

Emerging markets

Emerging market stocks are having an excellent year. Although they wobbled during the early stages of the Middle East conflict, they have since rebounded, helped by a handful of Asian semiconductor stocks such as South Korea’s Samsung and SK Hynix.

Lazard Emerging Markets Fund - which Fidelity’s investment director Tom Stevenson named as one of his fund picks in January - remained a popular choice in May. It mainly invests in Asia and Latin America and looks for companies that are cheaper than the market but with better fundamental prospects. It aims to outperform the MSCI Emerging Markets Index with less volatility.

Crucially, the fund steers clear of some of the Asian mega-caps. It doesn’t currently hold Samsung, for example, and underweights Taiwan Semiconductor Manufacturing Company (TSMC).

This is partly because fund manager James Donald is nervous about how the AI story is unfolding. “We’ve seen a market over the past six or seven weeks that has been extraordinarily difficult, and it’s all AI-related,” he told Fidelity. “In my opinion, it’s in a mania - and manias are very difficult to value or time.”

• Read: Tom’s fund picks for 2026

Past performance is not a reliable indicator of future returns

Source: Morningstar from 31.3.21 to 31.3.26. Basis bid to bid with income reinvested in GBP. Excludes initial charge.

Best-selling ISA funds in May

1. Fidelity Index World Fund
2. Royal London Short Term Money Market Fund
3. Fidelity Cash Fund
4. Polar Capital Global Technology
5. Artemis Global Income Fund 
6. Legal & General Global Equity Index Fund
7. Lazard Emerging Markets Fund
8. Vanguard FTSE Global All Cap Index Fund
9. HSBC FTSE All World Index Fund
10. Polar Capital Artificial Intelligence Fund

Source: Fidelity International. Net ISA sales 1 to 31 May 2026 for Personal Investors only.

• Open a Fidelity Stocks and Shares ISA

Best-selling SIPP funds in May

1. Fidelity Cash Fund
2. Fidelity Index World Fund
3. Royal London Short Term Money Market Fund
4. Fidelity Multi Asset Allocator Growth Fund (Retirement Builder)
5. Vanguard FTSE Global All Cap Index Fund
6. Artemis Global Income Fund 
7. Lazard Emerging Markets Fund
8. Legal & General Global Technology Index Trust
9. Legal & General Cash Trust
10. Legal & General Global Equity Index Fund

Source: Fidelity International. Net SIPP sales 1 to 31 May 2026 for Personal Investors only.

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Important information - investors should note that the views expressed may no longer be current and may have already been acted upon. Before investing into a fund, please read the relevant key information document which contains important information about the fund. Eligibility to invest in a SIPP or ISA and tax treatment depends on personal circumstances and all tax rules may change in the future. Withdrawals from a SIPP will not normally be possible until you reach age 55 (57 from 2028). Overseas investments will be affected by movements in currency exchange rates. Investments in emerging markets can be more volatile than other more developed markets. Reference to specific securities should not be construed as a recommendation to buy or sell these securities and is included for the purposes of illustration only. This information is not a personal recommendation for any particular investment. If you are unsure about the suitability of an investment you should speak to one of Fidelity’s advisers or an authorised financial adviser of your choice.