(Reuters) - Netflix Inc won back Wall Street's affections on Thursday, with several upgrades to its stock after the online video and DVD rental company signed up more U.S. subscribers than expected in the fourth quarter.

The Los Gatos, California-based company's shares soared some 21 percent to $118.84 in early trading on Nasdaq. The stock had dropped to a year's low of $62.37 on November 30, 2011.

Analysts at Citigroup, Barclays and J.P. Morgan Securities raised their price targets for Netflix, saying the customer growth may help alleviate investors' concerns about its ability to restart subscriber interest after a series of high-profile missteps.

Citigroup also upgraded the stock to buy from neutral.

Netflix, which outraged customers with a surprising price increase and a botched attempt to split off its DVD mail-service in 2011, added 610,000 net new subscribers in its home U.S. market, helping revenue leap 47 percent to $876 million.

Even with the upgrades, it would take a major positive run for Netflix to return to its former heights as a Wall Street darling, as recently as seven months ago when its shares peaked at $304 on July 13.

Some analysts maintained their price targets, urging caution as competition heats up in the online video space.

Netflix management acknowledged ongoing competition, including a potential stand-alone offering for Amazon.com Inc's video streaming product at a lower price.

In a letter to shareholders, Netflix Chief Executive Reed Hastings shrugged off competition from Amazon.com and Hulu Plus and said both services offered far less content.

We believe Netflix was a bit dismissive of the potential competitive threat here, but the degree of risk almost entirely depends on whether Amazon would approach such a service with its existing content library or whether it would be willing to step up spending dramatically to acquire more content, JP Morgan analyst Doug Anmuth said in a client note.

He said that in the end, competition with Amazon would not be good for the shares of either company.

As the company shifts customers from its DVD-by-mail service onto instant streaming, Netflix has been writing ever-heftier checks to acquire more TV programs and movies for its streaming service.