AJ Bell chief executive Michael Summersgill has warned that UK Isa reform plans have fallen into a 'black hole' as HM Revenue & Customs fails to finalize key rules. The investment platform boss told the Financial Times that proposed charges on cash held in stocks-and-shares Isas and moves to exclude cash-like products risk deterring first-time investors from entering the market.

Summersgill explained that newcomers typically start with cash or cash-like instruments before transitioning to stocks. HMRC's anti-avoidance measures could undermine the government's own goal of encouraging retail investment. The reforms, set to take effect next April, include reducing cash Isa limits from £20,000 to £12,000 for under-65s.

Despite regulatory uncertainty, AJ Bell reported robust half-year results, with revenue rising nearly 20% and statutory profit before tax increasing 33% to £92.8mn. The platform attracted a record 79,000 customers and £4.2bn in net inflows, sending shares up 13% to 603p.

The strong performance comes amid broader industry changes, as rival Hargreaves Lansdown implements new fee structures and cuts jobs to modernize operations. AJ Bell's success suggests investors are responding to competitive pressures in the investment platform market.