LONDON -- Asset manager Vanguard said on Monday that funds should carry health warnings about fees, though the U.S. giant rejected the idea of more radical fee changes proposed in a British regulatory review of the sector.

The Financial Conduct Authority launched the review last year saying it planned to overhaul Britain's 7 trillion pound ($9 trillion) asset management industry.

The regulator flagged widespread concerns about the performance of actively-managed funds relative to fees charged, the level of competition in the industry and the information shared with investors to help them make decisions.

In response to an FCA consultation, Vanguard, which specializes in low-cost index trackers and exchange traded funds, said warnings about fees should have equal prominence to warnings about past performance.

"Performance is a potential. Costs are a certainty, hence investors should focus as much, if not more, on costs," Sean Hagerty, head of Vanguard's European business, said in a statement.

"A 'health warning' on the impact of costs would be a clear sign of intent from the industry that it's putting the needs of the investor first."

Vanguard had $4 trillion in assets under management in total at the end of January, mainly in low-cost passive funds with about $1 trillion in active funds, a spokesman said.

The FCA proposed in an interim review of the sector in November that funds charge a single "all-in" fee, which analysts said would enable investors to see upfront what they are paying for trading costs.

But Vanguard said it doubted an all-in fee would be "accurate, objective or comparable", saying it would be more useful to give investors more information on how fees are charged, as funds were not uniform.

The New City Initiative, a lobby group for smaller funds, said an all-in fee could hit funds focused on less liquid strategies that incur higher dealing costs and favor bigger fund managers.

Dan Brocklebank, head of the UK arm of active fund manager Orbis Investments, which has more than 15 billion pounds under management, said there was enough scope for the FCA to enforce existing rules on fees, "before adding additional layers of regulation".

ICI Global, the international arm of the U.S. Investment Company Institute, also warned against the introduction of new regulations during a time of unprecedented disruption as Britain negotiates to leave the European Union.

The watchdog's final report, along with any proposed rule changes, is expected to be published in the summer. The deadline for consultation responses was Monday.