South Korean institutional investors loaded up on stocks in the final sessions of July, helping the local stock market keep its bullish run, data showed Tuesday.

In a turnaround from their net selling position, local institutions turned net buyers in the final four days of last month, purchasing a net 1.78 trillion won ($1.59 billion) for all of the month, according to the data by the bourse operator Korea Exchange.

Institutional investors had been net sellers till last Tuesday.

In contrast, foreign investors had recorded massive net buying before turning net sellers from last Monday, registering net selling of 522.9 billion won for all of July. Retail investors sold a net 867.8 billion won worth of stocks last month.

Strong foreign buying bolstered the stock market in the earlier part of July, but institutional purchases helped drive up the market in the final days, market watchers said.

"Despite end-of-month massive selling by offshore investors, heavy institutional buying helped prevent the key price index from going south," said Lee Kyung-min, an analyst at Daeshin Investment & Securities.

Powered mainly by foreign buying, the South Korean stock market had been on a tear in July, with the benchmark Korea Composite Stock Price Index hitting a record high of 2,451.53 on July 24.

Local institutions zeroed in on South Korea's top oil refiner SK Innovation last month with their buying of its shares standing at 239.6 billion won.

In comparison, foreign investors dumped shares of top-cap Samsung Electronics and chip giant SK hynix, with their net selling reaching a combined 1.76 trillion won.

"Institutions snapped up shares of companies that posted earnings surprises for the second quarter, while foreigners cashed in on gains in Samsung Electronics, SK hynix and other exporters," Lee said. (Yonhap)