A Baillie Gifford manager whose fund holds Hargreaves Lansdown shares has said the company needs to "grow up" in the aftermath of the Woodford saga.
Milena Mileva said she still backed Hargreaves as a long-term investment, but added the company needed to recognise its responsibilities.
Hargreaves has come under scrutiny since the summer when Neil Woodford was forced to suspend his flagship Equity Income fund. The platform had kept the fund on its Wealth 50 buy list until the day it was suspended, despite two prior years of poor performance.
Ms Milena said of Hargreaves: "They need to grow up. I would not want them to back away from [using buy lists] but I want them to grow up in how they deal with it.
"[Hargreaves] wants to evolve to become a wealth management platform, but it's how they do that which is the key part.
"Buy lists clearly play a role in a market where there's a lack of affordable advice but it's about how they do it - the process around how this is managed."
Ms Mileva manages the £272m Baillie Gifford UK Growth Fund, which has Hargreaves as its biggest holding at 4.4 per cent of the portfolio. Baillie Gifford is the third largest holder of Hargreaves Lansdown stock.
Mr Woodford's fund also featured in Hargreaves' multi-manager funds, which have experienced outflows since the saga.
Ms Mileva, who had multiple meetings with the team at Hargreaves after the Woodford Equity Income fund was suspended, said the company had handled the subsequent backlash as well as she could have hoped and had been "thoughtful about the follow-up".
But she acknowledged there had been an "error in judgement" in keeping the fund on the buy list.
However, she hoped the Financial Conduct Authority would not increase the regulation of platforms, such as Hargreaves, to a point which hampered their ability to run buy lists.
In the past the FCA has said buy lists were positive for consumers, arguing they helped create better investment outcomes.
Ms Mileva said: "They do need to think about what they need to do to make them better, but I hope the regulator does not challenge the proposition of them."
She added that she remained a long-term holder of the stock.
"I do not think it's their finest hour, but do I think it undermines the case for Hargreaves? No.
"Hargreaves are the best at what they do and their customers like them very much."
Hargreaves Lansdown declined to comment.
The Baillie Gifford UK Growth Fund has slightly underperformed its sector, the AIC UK All Companies, over the past three years, returning 25.7 per cent while its sector returned 27.4 per cent.