SAN FRANCISCO >> There’s some tech jubilance in the air on Wall Street and in Silicon Valley as a pair of newly public companies — Zoom and Pinterest — saw their stocks soar on their first trading day.

No one wants talk about a bubble, not to mention its prospects for bursting, but the strong initial performances might reassure investors with jittery nerves following ride-hailing company Lyft’s disappointing start less than a month ago.

Zoom Video Communications, which makes video conferencing technology people use for work, came out as a dark horse (or perhaps a dark unicorn), its shares surging about 81% when they began trading and ending the day up 72% at $62. Pinterest Inc., a much better known company that serves as a digital pinboard for people who want to see wedding, meal-planning, home renovation and other ideas, jumped 28% to close at $24.40.

Dan Morgan, senior portfolio manager for Synovus Trust, said an initial uptick is a good sign.

“It shows there is still strong demand in the tech sector,” he said.

The surge would be good news for Lyft’s larger rival Uber, which is due to go public in the next few weeks along with other possible tech IPOs from workplace messaging service Slack and data analytics company Palantir.

“There’s a lot coming down the pipe,” Morgan added.

Ben Silbermann, Pinterest’s CEO and co-founder, has long tried to distinguish the company from social media. Pinterest, after all, isn’t about sharing with friends and following celebrities. Still, as an ad-supported, consumer-facing business, it often gets lumped in with the likes of Snap, Twitter and Facebook.

“There are going to be some comparisons,” he said in an interview. But he added that, coming off of the company’s pre-IPO “road show” where he spoke to potential investors, he was “really happy how thoughtful investors were,” understanding that Pinterest is about “yourself” and not about entertainment or communication.

If they truly do, that could help Pinterest on the long run. Other high-profile companies, such as Twitter and Snap, also had strong initial trading days but then saw their stock prices fall substantially in the subsequent months. Just three weeks ago, Lyft also did well on its first trading day before Wall Street pumped the brakes. Its stock is now trading nearly 20% below its initial public offering price.

Pinterest joins a crowded market of ad-supported apps vying for people’s attention — and advertisers’ money. While the digital advertising space is dominated by Google and Facebook, Pinterest’s believers see the company as doing something different from both, inspiring people online to do something offline, whether that’s remodeling a kitchen or cooking some chicken parmesan.

“Pinterest is tastemakers … people who are curating or defining taste in areas you are interested in,” said Jeremy Levine, a partner at early Pinterest investor Bessemer Venture Partners. “A place to get you inspired about doing something in the real world.”

Levine said he doesn’t see Facebook and Google’s dominance in digital ads as an insurmountable duopoly. He pointed to the software business, where, historically, companies like SAP, Microsoft and Oracle, or Cisco with its WebEx video conferencing tool, were “hugely dominant.”

“Zoom came along and built just a better product,” he said. “They could persuade customers to come to a new vendor and go through the hassle of establishing a new relationship.”

For all the cautionary tales, there are companies like payment processor Square, which went public at $9 per share, rose 45% on the first day of trading and now sell for around $70.

San Francisco-based Pinterest has more than 250 million monthly users. Revenue, mainly through advertising, reached $736 million last year and the company posted a loss of $63 million.

Zoom, based in San Jose, California, had $330 million in revenue last year and profit of $7.6 million, making it one of the few profitable technology companies going public this year.