Opera hopes that its products will get a boost from the user base in China of Qihoo and Kunlun, which in turn hope to cross-sell their products and services to the Opera user base, and take advantage of Opera's mobile advertising platform.
Kunlun, which acquired in January a majority stake in dating site Grindr, is focused on mobile gaming development and publishing, besides app distribution, while Qihoo is a provider of Internet and mobile security products.
The other prospective buyers include investment companies like Golden Brick Silk Road (Shenzhen) and Yonglian (Yinchuan).
Opera said in August it had initiated a process "to evaluate and consider strategic alternatives" for the company, a process that was expected to be over in the second half of 2015. In December, it said the review would be completed in time for it to announce its earning for the full year 2015. On Wednesday, the company also announced its financial results.
The Oslo, Norway, company claims more than 350 million consumers worldwide. A longstanding player in the browser market, offering accelerated delivery of Web content using compression, Opera could not make it to the big league, particularly in the mobile market where Android and iOS phones dominate.
Its Opera Mini browser had 7.28 percent of the mobile phone and tablet market in January, compared to 41.57 percent for Chrome, 34.12 percent for Safari and 11.13 percent for the Android browser, according to Net Market Share.
The company has also launched apps like Opera Max for compressed download of videos and snaps across apps. It also ventured into Internet advertising through its Mediaworks unit.
The completion of the deal will depend on over 90 percent of the shareholders of Opera accepting the offer, among other conditions.