Snap Inc (SNAP.N) shares plunged on Wednesday after the Snapchat parent reported slowing user growth and revenue that missed analyst estimates amid stiff competition from copycat messaging apps.

Shares tumbled nearly 24 per cent in after-hours trading to US$17.58, wiping some US$5 billion from Snap's market capitalization in the latest reversal after a red-hot March initial public offering, which was the biggest for a U.S. tech company since Facebook Inc in 2012.

That performance echoed slides in Facebook and Twitter after they posted debut scorecards following their IPOs. Twitter shares cratered 24 per cent the next day, while Facebook's tumbled 11 per cent, still the biggest-ever one-day losses for both.

Snap said its daily active users (DAUs) rose 36.1 per cent to 166 million in the first quarter from a year earlier, marking a slowdown from the 47.7-per-cent rise for the fourth quarter and 62.8-per-cent jump for the third quarter that the company reported in its IPO filing.

J.P. Morgan had expected Snap's DAUs to hit 169 million in the first quarter, while Monness, Crespi, Hardt & Co Inc pegged them even higher at 173 million.

Snap's March IPO priced above the company's target range as investors put aside concerns about a lack of profits and voting rights to get a piece of the action. The IPO raised US$3.4 billion and gave the company a market valuation of roughly US$24 billion, and shares surged 44 per cent in their first day of trading.

Facebook, which made a US$3 billion bid for Snapchat in 2013, has upped the ante by offering camera-related features similar to Snap on its platforms, including Instagram and WhatsApp. The company said in April that Instagram Stories alone had reached 200 million daily active users.

Snap Chief Executive Evan Spiegel, who received a stock-based bonus worth nearly US$600 million for taking the company public, shrugged off imitations when asked about Facebook by an analyst on a conference call to discuss earnings.

"If you want to be a creative company, you've got to get comfortable with and enjoy the fact that people are going to copy your product if you make great stuff," he said.

Making a comparison to the search industry, Spiegel added: "Just because Yahoo has a search box doesn't mean they're Google."

Snapchat's growth was faster than Facebook, however, which said its overall daily user base grew 18 per cent year-over-year in the first quarter, as well as Twitter, which reported growth of 14 per cent in daily active users from a year earlier.

REVENUE DISAPPOINTMENT

Snap's revenue jumped nearly four-fold year-over-year to US$149.6 million but fell short of the average analyst forecast of US$158 million, according to Thomson Reuters I/B/E/S. Revenue was also down from the fourth quarter of 2016, a seasonally stronger period for ad sales, when it was US$166 million.

Revenue was "a relatively disappointing number," Pivotal Research analyst Brian Wieser said. "To their credit," he said, "they did guide towards a number that would be lower, which it was."

Average revenue per user was 90 cents US in the first quarter, Snap said, up from 33 cents US the same quarter a year earlier but below the US$1.05 per user in the fourth quarter of 2016.

Snap's net loss widened to US$2.21 billion, or US$2.31 per share, in the first quarter, from US$104.6 million, or 14 cents US per share, due to stock-based compensation related to the IPO.

Snapchat launched in 2012 as a mobile app that allows users to send photos, known as snaps, that vanish within seconds. The company rebranded as Snap Inc last year, and moved into the hardware space with Spectacles, its colorful sunglasses that record short videos to post on Snapchat.

Users created more than three billion snaps daily on average during the first quarter, up from more than 2.5 billion during the third quarter of 2016, the company said.

Snap receives some revenue from branded or sponsored filters and lenses, but depends on advertising dollars for the bulk of its overall revenue.

Digital marketing firm eMarketer in March had trimmed its 2017 U.S. advertising revenue forecast for Snap by US$30 million to US$770 million, citing higher-than-expected revenue sharing with the company's partners.

The total U.S. digital advertising market is meanwhile expected to reach US$83 billion, according to eMarketer, up nearly 16 per cent from last year.