More investors in South Korea are opting to short stocks as they took bearish bets on local equities following a recent strong rally, data showed Wednesday.

Daily stock short-selling averaged 360.5 billion won ($333.5million) in the main KOSPI and secondary KOSDAQ markets in April, 68 percent more than December's 214.6 billion won, according to the data compiled by the Korea Exchange. 

Stock short-selling is a trading technique in which investors sell stocks they borrowed on the belief that share prices will fall in the near future. When the prices fall, they can buy back the stocks at lower prices, pocket the profit and return the shares to the original owner. Increased short-selling typically indicates that many investors anticipate a fall in share prices.

The country's benchmark index, the KOSPI, broke the 2,100-point level to hit a nearly five-year high in mid-April, but it retreated for five consecutive days later that month to pare some of the early gains.

The daily short-selling volume was about 100 billion won in early April, but it quadrupled in late April.

Securities lending, a transaction in which an investor borrows a stock for a certain period of time for a fee, also went up in line with short-selling.

The value of borrowed stocks for short-selling and other measures amounted to 54.27 trillion won on the last trading day of April, adding 1.2 trillion won from the end of 2014, data showed.

Stock lending usually leads to an increase in short sales, meaning that investors are skeptical of a rise in the local stock market.

"Short-selling has risen as investors were betting that stock prices will slide after sharp gains in a short period of time," said Kim Young-il, a researcher at Daishin Securities. (Yonhap)