SEOUL (Reuters) - South Korean prosecutors indicted on Thursday Kim Beom-su, the billionaire founder of tech giant Kakao Corp, on charges of stock market manipulation, the Yonhap news agency reported.

The Kakao founder, who is also known as Brian Kim, was arrested last month and has been detained since.

He is seen as a visionary in South Korea's digital industry for building Kakao's group of affiliates - worth 86 trillion won ($62 billion) by assets - from the ground up since launching the popular messaging app KakaoTalk.chat in 2010.

Prosecutors say he was involved in manipulating the stock price of SM Entertainment in February last year to hinder a competitor, Hybe, from acquiring it.

Kim has denied the accusations, saying he never ordered or tolerated any illegal activity, the company said in a statement.

On Thursday, the tech giant posted an operating profit of 134 billion won ($97.24 million) in the second quarter, 18.5% up from a year ago.

Shina Chung, Kakao's CEO, told the post-earnings call that the company acknowledged shareholders concerns about the "difficulties from internal and external circumstances", but would continue to provide its services seamlessly.

She did not provide further details on the legal issue.

Former Kakao CEO Hong Eun-taek and former Kakao Entertainment CEO Kim Sung-soo have also been indicted without being detained, according to Yonhap.

($1 = 1,378.0900 won)

(Reporting by Hyunsu Yim and Ju-min Park; Editing by Ed Davies)