Lyft should stick with its single class of shares with one vote each when it debuts on the Nasdaq exchange as a switch to a dual-class structure imposes an unnecessary risk to potential shareholders, according to the letter.

If Lyft’s board fails to address the issue, it should adopt a provision to phase out the extra voting rights in seven years, it said.

The letter was signed by the UK’s Local Authority Pension Fund Forum, BNP Paribas Asset Management, pension funds representing public employees in New York, Los Angeles, Chicago and Ohio, the Teamsters union and United Auto Workers retirees, according to the newspaper.

Scott Stringer, the New York City comptroller who oversees the city’s pension funds, told FT that “outsized control among an unaccountable few is an unnecessary risk, and Lyft should go back to the drawing board.”

Securities and Exchange Commission Chairman Jay Clayton said earlier this week that getting rid of dual share classes means “you would choke off some very good companies from coming to market.”

Lyft declined to comment to Financial Times.