More than 20 brokerages cut price targets on the shares, which have fallen more than 50 percent since chief executive Jack Dorsey returned in July. The median price target for the stock is still $21, 50 percent higher than the current price.

Shares were last down more than 5 percent on the day, at one point hitting an all-time low of $13.91 a share.

Currently, 14 of 45 brokers have a "buy" rating on the company.

Starmine, a unit of Thomson Reuters, pegs the company's intrinsic value at $11.40 a share, implying further stock declines.

In its earnings report on Wednesday, Twitter said it had 320 million average monthly active users in the fourth quarter, unchanged from the third quarter and lagging a forecast for 323 million from RBC Capital Markets.

But Dorsey told analysts that monthly active usage in January "has bounced back to Q3 levels."

Facing slowing user growth, Twitter has been experimenting under Dorsey, who became interim CEO in July and then CEO in October, with ways to make its website more engaging.

But so far they have not paid off with additional user growth.

The company also issued weaker-than-expected guidance for revenue in the current quarter when it announced earnings.

It forecast first-quarter revenue of between $595 million and $610 million, well below the average analyst estimate of $627.1 million, according to Thomson Reuters I/B/E/S.

"Twitter can grow in three ways: first, it can expand its user base; second, it can expand the engagement of its users; and third, it can increase the frequency and pricing for ads delivered," said Michael Pachter of Wedbush Securities. "Presumably, Twitter is taking several steps to accomplish the second and third growth drivers, but it is not clear that it is doing much at all to accomplish the first."

But the company did exceed analysts estimates on fourth-quarter revenue and profits. Revenue rose 48.3 percent to $710.5 million, compared with estimates of $709.9 million, and earnings excluding items were 16 cents per share, above analyst expectations of 12 cents per share.

(Reporting By David Gaffen, the Bengaluru bureau, Jonathan Weber and Yasmeen Abutaleb; Editing by Meredith Mazzilli and Stephen R. Trousdale)