Foreign investors sustained a five-month buying streak in the South Korean stock market, resulting in an unprecedented quarterly volume.

The Financial Supervisory Service disclosed Monday that foreign investors amassed a total of 15.8 trillion won ($11.67 billion) worth of local shares in the first quarter of this year, marking the highest recorded amount since the agency started compiling data in 1998.

In March, approximately 5.1 trillion won streamed into the domestic stock market from overseas, marking the fifth consecutive month of net purchases by foreign investors. They made net purchases of 4.1 trillion won in the benchmark Korea Composite Stock Price Index and an additional 887 billion won in the secondary tech-laden bourse, Kosdaq, according to the agency.

This follows the foreigners' net purchase of around 7.8 trillion won in the local stock market in February and 3.5 trillion won in January.

Breaking down the recent activity, the FSS noted European investors made the largest purchases last month, totaling 3.3 trillion won, followed by American investors with 1.2 trillion won and Asian investors with 700 billion won.

In terms of the countries contributing to the inflow, investors from the United States and the United Kingdom led with net purchases of 2.2 trillion won and 1.1 trillion won, respectively. Conversely, investors from Canada dumped the most, totaling 1 trillion won, followed by Saudi Arabia with 600 billion won.

As a result, the aggregate volume held by offshore investors soared by 58.1 trillion won in the previous month, amounting to a total of 820.1 trillion won in Korean shares by the end of March. This represents approximately 29 percent of the entire market capitalization.

Among offshore investors, those from the US held the largest share at 40 percent, equivalent to 324.9 trillion won, followed by European investors with 256.5 trillion won and Asian investors with 120.3 trillion won.

The FSS added the foreigners also net purchased 2.36 trillion won of listed bonds and received 8.2 trillion won in repayment at maturity, net collecting a total of 5.85 trillion won. As of the end of March, the bond holdings totaled 244.3 trillion won -- 9.6 percent of the total bond market -- down 4.5 trillion won from the previous month.

Meanwhile, foreigners had mostly purchased shares in semiconductor and auto industries in the first quarter. According to the Korea Exchange, they scooped up 5.5 trillion won worth of shares of Samsung Electronics, the world's largest supplier of memory chips, followed by 2.14 trillion won worth of leading carmaker Hyundai Motor and 1.75 trillion won worth of shares in No. 2 chipmaker SK Hynix.