South Korea's financial stress index(FSI) surged into the "danger" range due largely to U.S. monetary tightening and increased volatility stemming from a credit crunch triggered by the developer of Legoland Korea.

According to data from the Bank of Korea(BOK) on Thursday, the FSI, based on real economic and financial indicators, stood at 23-point-six and 23 in October and November, respectively.

After gradually increasing within the “caution” range between March and September, the FSI surpassed the 22-point threshold to enter the “danger” zone the two previous months.

The BOK said that expanded market volatility from global monetary tightening and geopolitical risks combined with the unexpected credit crisis involving a default by the Legoland developer have restricted some intermediating functions of the bond and short-term money market.

It added that market stabilization measures taken by the government and the central bank itself have helped the FSI inch down in November.

Meanwhile, the ratio of private credit against the nominal gross domestic product(GDP) around the end of the third quarter stood at a record 223-point-seven percent, up one-point-four percentage points from the previous quarter. The ratio of corporate credit also jumped from 116-point-six to 118-point-five percent.