Pinterest Inc. has confidentially filed paperwork with the Securities and Exchange Commission for an initial public offering, according to people familiar with the matter, as the online-image search company joins a parade of highly valued technology startups planning to list their shares in 2019.

The company and its underwriters, led by Goldman Sachs Group Inc. and JPMorgan Chase & Co., are eyeing a late-June listing, some of the people said. They warned that, as always with IPOs and unpredictable markets, the timing could shift.