A group of Lyft Inc. investors is calling on the ride-hailing company to scrap its proposed dual-class share structure when it kicks off its IPO, saying the plan imposes "unnecessary and uncompensated investment risk on potential shareholders," the Financial Times reported March 17, citing a letter from the investor group.

In its registration document filed March 1, Lyft said its dual-class structure of shares will concentrate voting power with company founders Logan Green and John Zimmer, limiting investors' ability "to influence the outcome of important transactions, including a change in control."

Lyft's class B common stock has 20 votes per share, while its class A common stock to be offered in the IPO has one vote per share, according to the prospectus. Green and Zimmer's supervoting class B shares would convert to regular shares if their collective class B holdings fall below 20% of their stakes at the time of the IPO.

According to the FT, the founders' voting power under this structure will be lower than 50%.

The investor group, which is composed of pension funds, unions and assets managers in the U.S., U.K. and Europe, is reportedly urging Lyft to stick with its single class of shares. If that is not possible, the group said Lyft should adopt a "sunset" provision to phase out the extra voting rights within seven years.

"With a dual-class structure, Lyft is basically shielding itself and company insiders against shareholders who deserve a voice," New York City Comptroller Scott Stringer, who oversees the city's pension funds, reportedly said. "Outsized control among an unaccountable few is an unnecessary risk — and Lyft should go back to the drawing board," he added.

The FT said Lyft declined to comment on the letter.

Lyft and rival Uber Technologies Inc. are both set to go public this year. Uber was recently reported to be kicking off its listing in April, a move that could possibly lift its valuation to $120 billion, while Lyft is reportedly expected to reach a value of between $21 billion and $23 billion.

San Francisco-based Lyft is expected to begin its IPO roadshow March 18 as it plans to reach public markets before Uber does, the FT said.