(Reuters) - Shares of Netflix Inc hit a life-time high on Tuesday after the online video streaming service reported a rise in subscriber additions for the fourth straight quarter.

The stock was up 9.2 percent at $336.11, getting an extra boost after at least 12 brokerages raised their price targets. JP Morgan was the most bullish, pushing its target to $385.

"Netflix's content strength and the global, secular shift to internet entertainment are driving subscriber upside," JP Morgan analyst Doug Anmuth wrote in a note.

The company's market cap touched almost $146 billion at the stock's intra-day high. The shares have gained around 60 percent this year to become the top performer on the S&P 500 index <.SPX>.

Netflix added 1.96 million subscribers in the United States in the first quarter compared with 1.42 million a year earlier. It added 5.46 million subscribers in its international markets compared with 3.53 million last year. Both figures in the latest quarter came in above analysts' average estimate.

"We believe the breadth of Netflix's content offering is paying dramatic dividends in terms of subscriber adds and retention," RBC Capital Markets analyst Mark Mahaney wrote.

Netflix plans to invest around $8 billion on content this year.

Although Netflix is ahead of its peers, it faces stiff competition from Hulu, Apple Inc and Amazon.com Inc prime video. They have all been investing heavily to strengthen content, leading to price increases.

In January, Amazon raised the monthly fee for the U.S. version of its fast-shipping and video-streaming service Amazon Prime by $2. Netflix raised the price of some its plans in the U.S. and Europe last October.

The push for original content also comes at another price for Netflix as Walt Disney Co said it will stop providing new movies to the company starting in 2019, and plans to launch its own streaming service.

Analysts said Netflix was also benefiting from its wide range of agreements with wireless carriers and internet service providers, who are bundling Netflix streaming into their service offerings.

In the United States, T-Mobile (>> T-Mobile US), Verizon FiOS (>> Verizon Communications), Altice USA's (>> Altice USA Inc) Cablevision, Cox Communications and Comcast Corp (>> Comcast Corporation) offers Netflix subscriptions. Netflix has similar deals with Proximus in Belgium and SFR Altice in France.

"While these offerings so far are most prevalent in mature markets, leading to a lower Netflix average selling price and also lower churn, partnerships could also become more important in emerging markets," Canaccord Genuity analyst Michael Graham said.

Out of the 46 analysts that cover Netflix's stock, 26 rate it at "buy" or higher, 17 at "hold" and 3 at "sell" or lower.

(Reporting by Laharee Chatterjee and Jasmine I S in Bengaluru; editing by Patrick Graham and Bernard Orr)

By Laharee Chatterjee and Jasmine I S