IG unveils Fat Cat Index exposing ISA fee gaps

February 16, 2026

IG, a global online trading and investment platform, has launched its ‘Check Your Fees’ campaign after unveiling its first-ever ‘Fat Cat Index’, revealing that most UK investors are overpaying hundreds of pounds each year in Stocks and Shares ISA platform fees.

The new index highlights significant cost differences between major UK investment platforms offering comparable Stocks and Shares ISA services. According to IG’s analysis, more than half (52%) of investors are currently using the market’s 12 most expensive providers. The research categorises investors into three profiles based on trading frequency: passive investors making one trade per month, medium investors making three trades per month, and active investors making six trades per month.

For active investors using one of the 12 highest-cost platforms, annual fees are on average £515 higher than on lower-cost alternatives. Among those using the four most expensive providers, the average yearly overpayment increases to £711. Over a 40-year investment horizon, this could equate to nearly £28,440 in avoidable costs, based on current fee structures and excluding the impact of lost compounding returns.

Less active investors are also affected. Passive investors using one of the 12 higher-cost platforms pay an average of £263 more per year compared to low-cost alternatives, while those trading three times per month overpay by an average of £357 annually.

Alongside the index, IG surveyed UK retail investors holding Stocks and Shares ISAs and identified a substantial awareness gap. Nearly half (47%) of respondents have never calculated their total platform fees, and the same proportion report confusion over investment fee terminology, including FX spreads and tiered charges. Despite this, 55% believe they are paying the lowest possible fees, underscoring the complexity many face in understanding total investment costs.

The research also found behavioural barriers to switching providers. Almost half (48%) of investors cite the perceived administrative burden as a deterrent to moving platforms. Among investors aged over 55, 43% have remained with the same provider for more than a decade, while 34% say they are unlikely to switch.

Michael Healy, Managing Director, UK & Ireland at IG Group, said, “Most retail investors in the UK are being ripped off – paying hundreds of pounds a year in fees for a service they could access for far less by switching platforms. While investing was once expensive, it’s no longer the case, and there’s no reason for customers to miss out on compounded gains by paying through the roof in annual charges. That’s why we are calling on all UK investors to check their fees.

“We understand that investment fees can be complex. Between transaction charges, platform fees, subscriptions, and tiered pricing, it’s not always easy to work out exactly what you’re paying or to compare providers. But the likelihood is that if you’re paying multiple charges to invest, you’re probably paying too much. So if you can do just one thing this year as an investor, get on top of your fees – even small differences can make a huge impact over a lifetime.”