Twitter (TWTR  ) shares closed more than 20% down on Friday after the social media company reported a decline in monthly active users and weak guidance.

Earnings per share were 17 cents vs. 17 cents, according to a Thomson Reuters consensus estimate, while revenue stood at $711 million vs. $696.2 million. Monthly active users (MAUs) were 335 million vs. 338.5 million, according to StreetAccount and FactSet estimate.

Shares opened down 14%. The day's losses marked the worst single-day percentage drop since 2014 for the company, and the second worst in Twitter's history.

The company issued weak guidance as well, with adjusted EBITDA between $215 million and $235 million for the third quarter. The company expects stock-based compensation expenses to be in a range of $300 million to $350 million for the full year, down from the range of $350 million to $450 million previously expected. Capital expenditures will be in a range of $450 million to $500 million, up from a previous forecast of $375 million to $450 million.

Twitter's decision to delete bots and spammy accounts is a main driver behind lower monthly growth, but there are other factors as well. The company says that "many of the removed accounts have already been excluded" from the user figures it reports. Instead, Twitter's growth is hurting because the company isn't focusing on much outside of its cleanup effort.

"We are making active decisions to prioritize health initiatives over near-term product improvements that may drive more usage of Twitter as a daily utility," the company wrote in its earnings letter. "As we began 2018, we made deliberate decisions to allocate product and engineering resources that had previously been focused on product improvements designed to deliver growth in audience and engagement to projects related to preparing for GDPR and broader platform health."

Tech stocks tumbled yet again on Friday, as Twitter (TWTR  ) followed Facebook (FB  ) in delivering disappointing earnings. Intel (INTC  ) said a key new chip technology wouldn't be out until late next year, further placing a damper on the outlook for the tech industry which has increasingly lost its momentum.

"It's a continued reaction to earnings," said Brad McMillan, chief investment officer for Commonwealth Financial Network. "The big thing with Facebook is not what happened to the stock itself but what that means for the market. For the second time in a row, we saw two of the big tech stocks falter and investors are thinking, maybe the future isn't quite as bright as we could've assumed."

Some other market-leading tech stocks that serve as Twitter's mega-cap counterparts Apple (AAPL  ), Amazon (AMZN  ), Netflix (NFLX  ) and Alphabet (NASAQ: GOOGL) all lost more than 1.5% at their overnight lows, and the Nasdaq 100 index dropped 1.4% in regular trading hours.