Concerns are growing over a massive sell-off by foreign investors in the South Korean stock market amid fears of an economic downturn in the U.S.

According to the Korea Exchange on Monday, foreign investors sold approximately one-point-47 trillion won, or around one-point-zero-seven billion U.S. dollars, worth of spot stocks in the afternoon.

Monday's sell-off exceeded this year's previous high of one-point-33 trillion won in net selling on May 31.

Following record highs in domestic stock market indexes on July 12, foreign investors began selling, resulting in a net sell-off of two-point-572 trillion won, or one-point-87 billion U.S. dollars, worth of stocks in the KOSPI and KOSDAQ from July 12 to August 2, dragging down the indexes.

The sell-off by foreign investors is three times more than the net sales by institutional investors, which amounted to 888 billion won, or around 646-point-52 million U.S. dollars, while retail investors made a net purchase of three-point-819 trillion won, or two-point-78 billion dollars.