Baidu Inc., owner of China’s most popular online search engine, rose to a record in U.S. trading after reports about new services the company is developing.

The company said it is testing Web browsing software for personal computers, following a report earlier this week that it is planning to develop a mobile operating system. Sina Corp., which owns the Twitter-like Weibo in China, also jumped to a record on speculation it will gain users after Google Inc. said China’s government is blocking its e-mail service.

“There’s an opportunity to expand beyond the search business for Baidu by going to mobile,” said Aaron Kessler, an analyst at ThinkEquity LLC in San Francisco. The “growth potential is big right now in this core search market” and the new products are “still leveraging their search capabilities.”

The browser may put Baidu in direct competition with Microsoft Corp.’s Internet Explorer and Google’s Chrome. Chief Executive Officer Robin Li is expanding Baidu, also China’s biggest Internet company by market value, in social-networking and video after it took search-engine market share last year when Google moved its search service out of mainland China.

Baidu’s American depositary receipts rose 1.1 percent to $134.92 as of 4:30 p.m. in New York Friday, the highest closing price on record. The shares have risen for five straight days, bringing the weekly gain to 12 percent, the most in six months. 

The Nasdaq Composite Index advanced 3.8 percent this week, the biggest five-day gain since July 2010.

Sina, China’s third-most visited website, surged 17 percent this week, leading gains among the nation’s Internet companies after Google said it discovered Gmail was blocked by the Chinese government earlier in the week. NetEase.com Inc. rose 7.2 percent in the past five days while Sohu.com Inc. gained 6.2 percent.

“There’s still a lot of interest in Sina’s Weibo product. That has primarily been the driver for the company’s performance,” ThinkEquity’s Kessler said.

Baidu’s new desktop browser is being tested internally among employees and “dovetails” with the company’s “box- computing” technology, spokesman Kaiser Kuo said, without disclosing when it will be offered to the public. Earlier this week, he declined to confirm or deny a March 23 Financial Times report saying the company is planning to develop a “light operating system” for mobile devices. (Bloomberg)

Baidu accounted for 75.5 percent of China’s search-engine market by revenue in the fourth quarter, rising from 73 percent in the previous three months, according to research company Analysys International. Google’s share dropped to 19.6 percent from 21.6 percent, the research firm said.