The investor frenzy for shared electric scooters is cooling, as two leading startups lower their fundraising ambitions while dealing with vandalism, rising competition and other growing pains.

One of the companies, Bird Rides Inc., is planning to take on more investment at its current $2 billion valuation, people familiar with the discussions said. The year-old startup previously had told potential investors it was seeking hundreds of millions of dollars at a substantially higher valuation, but it shelved those plans because of a lack of interest, some of the people said.

That is a far cry from six months ago, when investors were so eager to get into the market that Bird’s value doubled in weeks to $2 billion in two successive rounds.

Its rival Lime also has scaled back, telling investors it expects to raise at a valuation of between $2 billion and $3 billion, below the roughly $4 billion it previously indicated to investors it was seeking, people familiar with those discussions said.

The valuations are still lofty—neither company is yet two years old—and the industry has plenty of backers. But some investors hope consolidation can stem losses. Uber Technologies Inc. has been considering an acquisition and in recent weeks has been in talks with Bird and Lime, people familiar with the matter said.