The boss of broker Hargreaves Lansdown has issued an apology following the suspension of a fund it sells.
Chris Hill, chief executive, said he shares clients' "disappointment and frustration".
The Woodford Equity Income Fund, managed by Neil Woodford, stopped investors cashing out this week.
In spite of the suspension of a fund it promoted to clients through its "Wealth 50" list of top buys, the firm stands by its research, Mr Hill said.
Mr Woodford, one of the UK's best-known stockpickers, suspended the fund after rising numbers of investors asked for their money back.
'Learn from it'
"I would like to apologise personally to all clients who have been impacted by the recent problems with the Woodford Equity Income Fund," Mr Hill said.
"We all share their disappointment and frustration. Our priority right now is to support our clients and keep them informed."
The UK's financial regulator "should have been awake" to problems at Mr Woodford's investment fund, former City Minister Lord Myners told the Today Programme on Friday.
He told the BBC the Financial Conduct Authority had missed "clear warning signs" that things were going badly.
"Our aim remains to provide the best possible service and choices to allow people to manage their investments simply and effectively," said Mr Hill. "The shortcomings of one fund should not detract from the benefits of favourite fund lists like the Wealth 50.
"We are confident in the robustness of how we analyse, research and compile our favourite fund list with a focus on ensuring best value for customers; nonetheless, we are reviewing this specific situation to ensure we learn from it and address it for the benefit of our customers going forward."
On Monday, Hargreaves Lansdown dropped the Woodford fund off its favourite list. On Wednesday, it bowed to pressure to drop its platform fee for Woodford investors.
Investors are charged both by their broker and the manager themselves. While Hargreaves Lansdown cut its fee, Mr Woodford has not cut his management fee.
On Thursday, chair of the Treasury Committee Nicky Morgan said investors in the Woodford Equity Income Fund should not be charged management fees while trading in the fund was suspended.