An investor walks out of the Lyft roadshow with documents in hand at a hotel in New York, New York, U.S., March 21, 2019.

Lyft is in the process of courting investors, but potential buyers still question how and when the company will make money.

The ride-hailing start-up is wrapping up the first week of its "roadshow," a series of presentations across major U.S. cities ahead of its highly-anticipated public offering. Multiple potential investors attending Thursday's lunch, hosted by Credit Suisse, told CNBC they were skeptical about profitability.

Lyft executives told hundreds of investors on the 20th floor of the St. Regis that the company will eventually reach 20 percent EBITDA margins, but gave no clear timeline for that watermark, according to three investors who asked not to be named because the meeting was private.

The San Francisco-based company also projected 70 percent long-term gross margins, also without a timeline. Media is not allowed in the presentations, but CNBC spoke to investors as they were walking out of the hotel in Midtown Manhattan.

Much like its rival Uber, Lyft is losing money. The second-largest ride-hailing company reported a $911 million loss on $2.1 billion in revenue last year, according to its IPO prospectus filed in early March. Lyft, which plans to list on the Nasdaq next week, said it expects sales to grow faster than its losses.

One attendee said executives "punted" to Wall Street research analysts on questions about specific growth numbers and financials, largely because executives are limited on what they can share due to disclosure rules for roadshows. When probed by an attendee, Lyft executives also declined to say whether there was a model city that shows how they can achieve profitability, one investor said.

The company told the group, over a lunch of Caesar salad with chicken, that it would keep spending this year before pulling back to focus on profits.

"They said 2019 would be the peak investment year," Gabelli research analyst Shawn Kim told CNBC outside of the St. Regis. "It was a measured approach but lacking on details on how they're going to get there."