SHANGHAI (Reuters) - Tencent Holdings is planning to shut down access to its popular instant messaging platform for millions of users after a public spat with China's top antivirus software provider, Qihoo 360.
Tencent is making users choose between running its QQ messaging platform, China's largest with more than 600 million users or Qihoo 360's antivirus software.
"We have just made a very difficult decision ... We have decided that computers running 360 software will not be able to run QQ software," the firm said in a statement.
Tencent, China's largest Internet firm by market capitalization, and Qihoo 360, China's top provider of free security software, have been involved in a tussle for more than a month accusing each other of bad business practices, such as spying, hacking and leaking users' privacy.
Tencent shares fell 3.7 percent by the midsession break, underperforming the broader Hang Seng Index which was up 1.3 percent.
"Basically the shares are down because people are concerned that the impact of the spat between 360 and Tencent," said Paul Wuh, a Hong Kong based analyst with Samsung Securities.
Qi Xiangdong, Qihoo 360's president was quoted by the official Xinhua news agency as saying Tencent's move would be disastrous for China's Internet population, the world's largest at 420 million.
Qihoo could not be immediately reached for comment.
Reporting by Melanie Lee; Editing by Jacqueline Wong and Lincoln Feast