SAN FRANCISCO — Lyft’s debut on the stock market is off to a bumpy start.

The ride-hailing company went public in a blaze of glory on Friday, as its stock jumped 8.7 percent from its initial public offering price of $72 a share. On Monday, in its second day of trading, Lyft’s stock plunged nearly 12 percent to below $72, closing the day at $69.01.

The rapid decline raises questions about investors’ appetite for fast-growing but unprofitable tech companies. While Lyft has been expanding and gaining new revenue, it lost nearly $1 billion last year. Ride-hailing companies often subsidize the cost of rides and pay incentives to drivers, which is expensive. And Lyft is also spending heavily on initiatives including electric bikes and self-driving technology.

Other tech companies that went public while recording large losses, such as Snap, Twitter and Groupon, also eventually fell below their offering prices.