April 17 (Reuters) - Shares of Weibo Corp, the owner of a Chinese Twitter-like messaging service, rose as much as 14.6 percent in their U.S. debut, overcoming worries about the outlook for tech sector and concerns that censorship in China was affecting its user growth.
Weibo's debut was being closely watched as it comes ahead of the much-anticipated IPO of Chinese e-commerce giant Alibaba Group Holding Ltd <IPO-ALIB.N>.
Alibaba, which holds a stake in Weibo, is expected to file as early as next week for a U.S. IPO that could raise as much as $15 billion. That would make it the biggest internet company IPO since Facebook Inc's $16 billion IPO in 2012.
Weibo's shares had been priced at the bottom end of the target range of $17-19, and the size of the offering had been cut to 16.8 million American Depositary Shares from 20 million.
The shares touched a high of $19.49 in early trades on Thursday, valuing the company at $3.97 billion.
The offering, whose lead underwriters were Goldman Sachs (Asia) LLC and Credit Suisse, raised $286 million for Weibo.
Companies have been taking advantage of a strong equity market to launch IPOs.
U.S. IPOs raised more than $18 billion in the first three months of the year, making it the best quarter in more than a decade. Technology companies raised about $4 billion of the total, compared with $1 billion in the same period last year.
Investors appear to be having second thoughts, however, as valuations - particularly for tech and biotech companies - become stretched.
The tech-laden Nasdaq Composite index has fallen about 6.5 percent since its March 6 high, and recorded its biggest one-day drop in 2-1/2 years last week.
Weibo, whose name means "micro blog" in Chinese, has grown at a breakneck speed in a country where Twitter Inc is banned, but its user growth has slowed as China cracks down on criticism of the ruling Communist Party.
A rule that took effect in September imposes a prison sentence of up to three years for those who knowingly share false information online.
The crackdown had a chilling effect on Weibo postings. Research commissioned by Britain's The Telegraph newspaper found that posts fell as much as 70 percent after rule was announced.
According to the same research, the number of highly active Weibo users - those who post at least 40 times a day - fell from a peak of 430,000 in March 2012 to 111,000 in December 2013.
SWITCH TO WECHAT
People who once used sites such as Weibo's are now flocking to messaging apps such as Tencent Holdings Ltd's WeChat.
Unlike Weibo, where messages can reach millions of people in minutes, WeChat allows users to communicate in small, private circles of friends, and send text and voice messages for free.
WeChat, meaning "micromessage", leaped from 121 million global monthly active users at the end of September 2012 to 272 million in just a year.
However, WeChat is not immune to government censorship. Last month, authorities closed dozens of popular accounts, including those held by widely read columnists and investigative journalist Luo Changping.
Weibo is controlled by Web portal company Sina Corp , whose stake falls to 56.9 percent from 77.6 percent after the IPO.
Alibaba, which paid $585.8 million for an 18 percent stake in the company last year, will increase its holding to 32 percent and will also appoint a director to the board.
Weibo often prompts comparisons with Twitter but its market value is a fraction of that of the San Francisco-based company. At Wednesday's close, Twitter was valued at about $26 billion.
(Reporting by Tanya Agrawal in Bangalore and Yimou Lee, Elzio Barreto and Denny Thomas in Hong Kong; Editing by Ted Kerr)