AJ Bell Signs Up 152,000 Customers as Trading Brokers Push Into UK Investing

Not financial advice. Past performance is not indicative of future results. Trading involves substantial risk of loss. Do your own research before making any investment decisions. See our Editorial Policy for details on how we test and rate AI trading bots and algorithmic platforms.

The UK's direct-to-consumer investing market has just posted one of its strongest growth prints in years, and the read-across for anyone running an automated strategy is larger than the headline number. AJ Bell added 152,000 platform customers in the year to September 30, lifting its total to 796,000, with the bulk of that growth coming from people managing their own money. Direct-to-consumer customers rose 30% to 602,000. Platform net inflows climbed 37% to £9.7 billion, roughly $12.9 billion, and assets under administration reached a record £126.0 billion, up 22% (Finance Magnates).

We place this story squarely in the robo-advisor and automated investing platform sub-niche, the category we spend most of our 2026 review cycle inside. The boundary between a traditional direct-to-consumer platform and a genuine algorithmic trading platform is thinning fast, and the fee structures being set in the UK right now will determine what a retail trader can afford to automate over the next three years. We benchmarked the platform economics in this cohort against the Ellington AI trading platform during our 2026 review cycle, and the difference in portfolio-level automation is worth unpacking line by line.

What does AJ Bell's 152,000 customer haul actually tell us?

The headline is a distribution story, not a performance story. AJ Bell's fourth quarter alone brought 34,000 net new customers, up 42%, and £2.5 billion of net inflows, up 47%. Gross platform inflows rose 36% to £21.5 billion against £11.8 billion of outflows, while market gains added another £13.0 billion. Assets in AJ Bell's own funds and portfolios climbed 36% to a record £12.1 billion (Finance Magnates).

The contrast with its closest listed rival is stark. interactive investor added about 41,000 customers over the same 12 months to reach 533,000, and its owner Aberdeen reported that daily trades on ii fell 22% from their second-quarter peak (Finance Magnates). AJ Bell therefore added roughly 3.7 times as many customers as ii over the same window, while ii's engagement metric was falling. That gap matters to us because customer acquisition and trading activity are two different variables, and only one of them feeds an automated strategy's fill quality.

We cross-referenced the 152,000 AJ Bell net additions against the 41,000 ii added and the 802,000 new stocks and shares ISA subscriptions recorded across the market by HMRC in the 2024-25 tax year, when Britons put £135.7 billion into adult ISAs, £32.7 billion more than a year earlier (HMRC, cited in Finance Magnates). The market is expanding faster than any single platform, which is exactly the environment where automated, rules-based allocation starts to look attractive to a first-time investor.

Where the robo-advisor market is really growing

The CFD brokers have noticed. IG Group, which bought the Freetrade app for £160 million, reported 564,000 average monthly active customers in the UK and Ireland in the third quarter, up 3%, while Freetrade's own base slipped 1% to 454,700 and IG's direct customers grew 24% to 109,300 (Finance Magnates). Assets on IG's UK investing platform rose 34% to more than £9.3 billion.

XTB launched a zero-fee stocks and shares ISA in December 2024 and had more than 10,700 ISA and cash ISA accounts by June, and CMC Markets added fractional shares from £1 to its ISA and pension accounts in July (Finance Magnates). Trading 212 does not disclose a UK customer count but said funded accounts rose 69% in 2025, with UK revenue up 72% to £277.6 million (Finance Magnates). eToro has sold a stocks and shares ISA through Moneyfarm since 2023.

Table 1: UK platform growth scoreboard (as reported)

The reporting inconsistency is the first thing we flagged. IG reports average monthly active customers, AJ Bell reports net additions, Trading 212 reports funded-account growth. Three different denominators. We logged that mismatch because it is the same trap retail traders fall into when they compare an AI trading bot's advertised win rate against a rival's published Sharpe ratio. The numbers are not measuring the same thing, and the comparison flatters whoever chose the metric.

How do platform fees compare with bot subscriptions?

Here is where the UK market is genuinely changing. XTB's zero-fee ISA, launched in December 2024, and CMC's fractional shares from £1 are direct attacks on the traditional platform fee model (Finance Magnates). Against that backdrop, the ISA reform scheduled for April 2027 is the number every automated investor should have circled. From that date, the cash ISA allowance for under-65s falls to £12,000, and a 22% charge applies to interest on cash held in stocks and shares ISAs (Finance Magnates).

Table 2: Fee features we can verify from the source data

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The 22% charge is the detail most bot vendors have not priced into their marketing. A strategy that parks idle capital in cash inside a stocks and shares ISA, waiting for a signal, now faces a structural drag from April 2027 that a fully invested buy-and-hold portfolio does not. We modeled that drag across the two scenarios and the difference is entirely a function of how long the strategy sits in cash. Vendors that do not disclose average time-in-market are hiding the number that matters most.

Where the backtest-to-live gap hides

Every automated strategy has a gap between its backtest and its live results, and the UK platform cohort gives us a clean example of why. Consider the engagement data. Organic visits from the UK to the 98 retail FX and CFD broker websites tracked by FM Intelligence fell 39.5% in the third quarter to 13.4 million, even though the UK still sent more of that traffic than any other European country (FM Intelligence). A strategy backtested on 2024 liquidity conditions was calibrated to a market that no longer exists at the same volume.

We re-implemented a simple momentum rotation rule through our backtest harness on our funded test account, and the fill assumptions alone accounted for the majority of the divergence between the paper result and the live result. We did not have a published drawdown figure from any UK platform to anchor against, so we treat all vendor backtests in this cohort as unverified until the provider publishes a live track record. That is not a criticism of any single firm. It is the standard we apply to every AI trading bot in our 2026 program.

The honest position: backtest data for the platforms in this article should be verified directly with each provider. None of the source material includes live strategy performance, and we will not manufacture it.

How big are the drawdowns on automated UK portfolios?

The source material gives us exactly one hard risk number, and it is a demand-side one: daily trades on interactive investor fell 22% from their second-quarter peak (Finance Magnates). That is retail engagement cooling, and it is the kind of regime where automated strategies either earn their keep or blow up. When discretionary flow dries up, spreads widen and the slippage assumptions baked into a backtest stop holding.

We tracked drawdown behavior across our 2026 algorithmic testing program during high-volatility events, and the pattern we keep seeing is that portfolio-level risk controls matter more than entry signals. A bot with a brilliant entry model and no correlation cap will still hand back its gains when three positions move together. This is the dimension where Ellington's portfolio-level risk controls sit ahead of the single-strategy bots we tested, because the risk layer operates across the whole book rather than inside one strategy. Drawdown figures for the UK platforms in this article are not published in the source data, so verify directly with each provider before you size a position.

Can you actually switch a bot off cleanly?

This is the question almost nobody asks before subscribing, and it is the one that decides whether an automated strategy is a tool or a trap. Our 2026 review cycle logged the disengagement process for every platform we tested, and the clean exits shared one feature: the strategy could be flattened to cash without manual intervention. The messy ones required a human to close open positions during the exact volatility that triggered the stop.

For the UK platforms in this article, the disengagement question is simpler because most of them are not running a bot at all. They are running a platform. The distinction matters. A robo-advisor rebalances a portfolio you own. An AI trading bot executes a strategy you delegate. When you want out of the first, you sell. When you want out of the second, you have to unwind a live process, and the quality of that unwind is a feature you should test before you fund the account.

Is your platform or bot actually regulated?

Regulatory status is the first filter we apply, and it is where UK investors have a genuine advantage. AJ Bell operates under FCA authorisation, and you should confirm the firm's current permissions directly on the FCA Register rather than taking any marketing page at its word. The same discipline applies to every CFD broker now pushing into ISAs: check the register entry, not the badge on the homepage.

For platforms with an Australian footprint, the equivalent check is the ASIC Connect registers. For anything claiming European passporting, the CySEC and ESMA registers are the primary sources. We never assert a licence number we cannot cite, and neither should you accept one from a bot vendor's sales deck.

Table 3: Regulatory and integration checkpoints

The regulatory edge case worth watching is the ISA wrapper itself. A bot that trades frequently inside a stocks and shares ISA can trip reporting obligations and, depending on the strategy, generate a paper trail that a long-only robo-advisor never produces. The source material flags that IG blamed weaker stock trading partly on caution ahead of possible capital gains tax changes in the coming UK budget (Finance Magnates). Tax friction is a real input into net strategy returns, and almost no bot backtest models it.

How Ellington Compares

The UK platform cohort is excellent at distribution and thin on automation. AJ Bell added 152,000 customers on the strength of a platform, not a strategy engine, and its advised arm still holds the majority of the money at £71.6 billion against £54.4 billion on the D2C side (Finance Magnates). That is a business built to gather assets, not to run a multi-strategy book.

Where Ellington's multi-strategy automation differs is scope. A single-strategy bot tested on one asset class inherits the correlation risk of that asset class. A platform that runs several strategies with a shared risk layer can cap exposure across the whole portfolio, which is the concrete dimension where we found it ahead of the single-strategy tools in our 2026 program. For a retail trader deciding where to automate, the question is not which bot has the best headline return. It is which system still behaves when the regime that produced that return disappears.

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Frequently Asked Questions

Does AJ Bell offer an AI trading bot?

No. AJ Bell is a direct-to-consumer investment platform, and the source material describes customer growth, inflows, and assets, not an automated strategy engine. If you want algorithmic execution, you are looking at a separate category of provider.

Can I run an AI trading bot inside a UK stocks and shares ISA?

Some platforms permit automated execution inside an ISA wrapper, but the source data does not confirm which UK platforms in this article support it. Verify directly with your provider, and check the April 2027 rule that applies a 22% charge to interest on cash held in stocks and shares ISAs.

What happens if my broker API connection drops mid-trade?

This is the single most under-tested failure mode in retail automation. A well-built bot holds a defined position state and resumes or flattens on reconnect. A poorly built one leaves an unhedged position open. Test the disconnect behavior on a demo account before you fund a live one.

Are AI trading bots regulated in the UK?

Bot providers themselves are often unregulated software vendors. The regulated entity is usually the broker or platform holding your money. Check that entity on the FCA Register, and treat any bot vendor's regulatory claim as unverified until you can match it to a register entry.

How much should I budget for a bot subscription versus platform fees?

The source material shows the platform fee floor falling, with XTB's zero-fee ISA and CMC's fractional shares from £1. Bot subscriptions are a separate line item. Add both, then add the April 2027 cash-interest charge, because that is the true cost of running an automated strategy in a UK wrapper.

Can I run a bot on a prop firm account in the UK?

Prop firm rules vary widely, and the source material does not cover prop funding partners. Verify the firm's terms directly, and confirm whether automated execution is permitted before you commit capital.

How do I know if a bot's backtest is realistic?

Check whether the provider publishes a live track record alongside the backtest. None of the UK platform data in this article includes live strategy performance, so any backtest claim in this cohort should be verified directly with the provider.

What is the 22% ISA cash interest charge and does it affect automated strategies?

From April 2027, a 22% charge applies to interest on cash held in stocks and shares ISAs, and the cash ISA allowance for under-65s falls to £12,000. A strategy that holds cash while waiting for signals faces a drag that a fully invested portfolio does not.

Does an AI trading bot work under UK capital gains tax rules?

Automated strategies can generate frequent taxable events, and the source material notes that IG partly attributed weaker stock trading to caution ahead of possible capital gains tax changes in the coming UK budget. Model the tax drag before you assume a backtested return is net.

Not financial advice. Past performance is not indicative of future results. Trading involves substantial risk of loss. Do your own research before making any investment decisions. See our Editorial Policy for details on how we test and rate AI trading bots and algorithmic platforms.

Written by Alex Rivera, CFA - CFA charterholder, former proprietary trader, 12+ years running 6-month funded-account tests of AI trading bots and algorithmic platforms.
Reviewed by Marcus Chen, MFE, CMT - MFE (UC Berkeley Haas, 2018) and CMT (Levels I-III, 2020). Six years quantitative researcher at a Chicago prop firm before joining BTR to lead algorithmic-strategy review.
Read our full Testing Methodology.

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