True
The KOSPI tumbled 5.5% in a sharp selloff, and US semiconductor stocks also declined in the same period, extending pressure on the chip sector across both markets.
The 5.5% drop in the KOSPI marked a steep one-day decline for the Korean benchmark index. The fall coincided with renewed losses in US semiconductor shares, which also moved lower, according to the available record.
US chip equities had already been trending downward, and the latest session added to those declines rather than reversing them. The parallel weakness in Korean and US semiconductor-linked stocks underscored the sensitivity of the KOSPI — where Samsung Electronics and SK hynix carry heavy index weight — to movements in the US chip sector.
The extent to which the US semiconductor decline directly caused the KOSPI's 5.5% plunge is not established in the available record, which confirms only that both declines occurred together.
The claim that the KOSPI fell 5.5% while US semiconductor stocks also declined again is True.