The interactive investor (ii) index: Q2 2025

• The average ii customer outperformed the IA Mixed Investment 40-85% Shares sector across all time frames examined
• Those aged 34-45 outperformed their peers, seeing their portfolios grow by almost 37% over the five and a half year period
• Investors look to cash alternatives during market volatility, with the T26 gilt and Royal London Short Term Money Market Fund in the top holdings across most age ranges
• This index includes a new section: Investor Focus where ii’s fund experts delve into investment trends and what to watch 
• To view the full report, please click here

interactive investor (ii), the UK’s second-largest platform for private investors and leading flat-fee platform, has published its latest instalment of the ii Index, providing data and insights on how the everyday retail investor is performing and positioning their portfolios in this ever-changing market. 

• Invest with ii: SIPP Account | Stocks & Shares ISA | See all Investment Accounts

This iteration of the ii Index includes a new outlook section: Investor Focus, which outlines key investor themes to watch.

To view the full report, please click here.

Consistent strong performance of ii customers

This index has tracked five and a half years of data. Which shows that the average ii customer has seen their portfolio grow by 33.1% - beating the aggregated performance of funds in the IA Mixed Investment 40-85% Shares sector (27.3%).

The sector can be a useful comparator for private investor portfolios, given its mix of bonds, cash, and equities.

Performance data to 30 June 2025. Source: interactive investor/Morningstar.

Camilla Esmund, Senior Manager at interactive investor, says: “We’ve seen impressive ii customer performance. Not only over the last quarter, but also the last five years. Market volatility is part and parcel in investing in the markets, which is why it’s important to diversify and have a long-term investment horizon. The last few months are case-in-point, particularly in April after the so-called ‘Liberation Day’ across the pond and the impact of the ‘Trump tariffs.’ But we can see that this hasn’t deterred investors.

“In fact, this same period of volatility also saw our busiest ever trading day on April 7th, with more purchases than sells. Our customers kept calm and carried on, and some took this as an opportunity to bolster their portfolios. This is a consistent trend; in fact, interactive investor customers are a great case study in getting the fundamentals of investing right – helping to weather geopolitical storms and market uncertainty without panic-selling.”

Age analysis - performance

Esmund continues: “Investors across all of our age groups outperformed the IA Mixed Investment 40-85% Shares sector over the five-and-a-half-year period, but those aged 35-44 have performed the best over the longest time frame. The not-so-secret to the strong performance? Diversification – as we can see that on average they have balanced portfolios but with the most weighting towards funds (30%), followed by equities (27%), and then ETPs (largely comprised of ETFs or exchange-traded funds).”

Portfolio breakdowns across ages

ETFs continue their steady growth in popularity on the ii platform, with those aged 25-34 putting the most money into them at 20%. This is closely followed by the strongest-performing age group, the 35-44s, who allocate 19% of their portfolios to them. Older investors, however, allocate 6% of their portfolios to these types of funds.

When it comes to equities, there’s a vast difference between our youngest and oldest investors – with those aged 18-24 allocating 21% of their portfolio to stocks, versus those aged 65+ allocating almost double the amount at nearly 40%.

Investment trusts are most popular with those 65+, who allocate nearly 25% of their portfolios to them. This is starkly contrasted by those aged 35-44 and 45-54, who only allocate 8% and 10% of their portfolios respectively.

Passive funds continue to dominate across all age ranges. Across the top holdings across all age ranges, 60 in total, 22 of these are passives. This is down slightly on last quarter, where 24 were passive funds.

Cash alternatives prove popular 

The Royal London Short Term Money Mkt fund has entered the top holdings lists strongly this quarter, likely due to the period of market volatility which stemmed from the start of Trump’s tariffs back in April. The fund now appears in every top 10 list apart from those aged 25-34 and 65+.

On a similar vein, other cash alternatives also entered strongly in the top holdings lists, with the UNITED KINGDOM 0.125 30/01/2026 (LSE:T26) gilt featuring in every top 10 list apart from those 18-24 and 65+.

Kyle Caldwell, Funds and Investment Education Editor, at interactive investor: explains:“On the risk spectrum, money market funds are at the low-risk end, due to investing in high-quality bonds with short lifespans and making use of other very short-term savings instruments offered by banks. Such funds aim to generate a ‘cash-like’ return.

“The past couple of years have been an opportune time to consider money market funds due to interest rates rising from rock-bottom levels to a peak of 5.25% in the summer of 2023. The income that money market funds generate, although not guaranteed, tends to be close to the level of UK interest rates.

“Therefore, when rates are cut, money market funds will pay less income. With the UK interest rates currently 4.25%, investors are still pocketing an inflation-beating income for low risk.

“However, it is important to stress that while cash and bonds form an important part of a balanced portfolio by being ‘defenders’, and that they can meet short-term income needs, equities are the key piece of the jigsaw to grow wealth in real terms over the long term.”