Foreign investors' biggest buying spree in 45 months fueled the latest rally on the benchmark KOSPI in January.

The Korea Exchange(KRX) said Wednesday that overseas investors picked up a net four-point-05 trillion won worth of shares on the KOSPI last month, the highest monthly tally since they scooped up just under four-point-65 trillion won in shares in April 2015.

In January, retail investors had offloaded some three-point-23 trillion won in shares, with institutions selling 843-point-one billion won in stocks more than they bought.

The KRX said thanks to the strong buying by foreign investors, the overall KOSPI rose eight-point-03 percent last month.

The index hit two-thousand-203-point-46 last Friday, which is roughly on par with the average reading tallied last October.

Foreign investors' buying spree comes after share prices had dropped to reflect the sudden market plunge in the fourth quarter last year, and amid an easing of risk factors including the U.S.-China trade dispute and the U.S. Fed's deflationary policy.