Ride-hailing firm Lyft Inc. recently selected underwriters for an initial public offering that is expected in the first half of 2019, according to people familiar with the company’s plans.

JPMorgan Chase & Co. will lead the offering along with Credit Suisse Group AG and Jefferies Group LLC, while several additional banks will hold smaller roles, these people said. Lyft’s valuation is expected to top the $15.1 billion it was valued at earlier this year, some of the people said, though private valuations can change until...