Interactive Investor ISA & SIPP Review 2026

Overview

Interactive Investor (ii) is the UK’s second-largest direct investment platform, and the leading flat-fee option for UK investors. Instead of charging a percentage of your portfolio, ii charges a fixed monthly subscription — making it dramatically cheaper than percentage-based platforms for larger portfolios. ii is FSCS-protected up to £85,000, the standard level for any FCA-regulated UK platform.

The flat fee advantage

The Core plan costs £5.99/month (£71.88/year) and covers portfolios up to £100,000, regardless of whether you have £10,000 or £100,000 invested. For a £100,000 portfolio, this compares to £373/year at Hargreaves Lansdown — a saving of over £300/year. Portfolios above £100,000 need the Plus plan at £14.99/month (£179.88/year), which has no upper limit. There’s also a Premium plan at £39.99/month for investors wanting additional research and tools, though Core or Plus covers most needs.

Crucially, one subscription covers your ISA, SIPP, and GIA together — since February 2026’s pricing overhaul, there’s no separate SIPP fee on top. If you hold both an ISA and a SIPP, you pay a single monthly fee for both, which is a real advantage over percentage-fee platforms that charge separately per account.

Dealing costs £3.99 per trade, with no free trades included.

Who is ii best for?

• Investors with portfolios over £50,000 where the flat fee beats percentage charges
• Long-term buy-and-hold investors who trade rarely, since dealing costs £3.99/trade with no free trades included
• Investors who want a broad range — ii offers the same breadth as HL

Who might prefer alternatives?

• Investors with portfolios under £30,000 where the flat fee is disproportionately expensive
• Passive ETF investors who only need ETFs and could use InvestEngine for free

Verdict

ii is the natural upgrade from HL for investors whose portfolios have grown. The crossover happens around £50,000 for most funds investors. Use our calculator to find your exact crossover point.