SAN FRANCISCO — Pinterest has avoided many of the woes of other newly public tech companies. But on Thursday, it stumbled.

In its first earnings report since going public last month, the digital pinboard company posted a narrower loss than a year earlier and a 54 percent increase in revenue. But its earnings per share failed to meet Wall Street expectations, sending its stock tumbling more than 15 percent in after-hours trading.

The results followed the bumpy stock market debuts of several tech companies in recent months. Last week, the stock of the ride-hailing giant Uber dropped on its first day of trading, and has struggled ever since. Shares of Uber’s rival Lyft, which were listed in March, have also fallen below their offering price. Those performances have raised questions about investor appetite for fast-growing but unprofitable tech firms.

Some smaller tech companies that are losing less money have seen their share prices soar after their recent I.P.O.s. They include Zoom, a video conferencing software company; PagerDuty, a cloud computing company; and Beyond Meat, a meat-alternative company.