South Korean stocks ended lower Wednesday as investors attempted to cash in recent gains while weighing the odds of a debt ceiling deal passing US Congress. The local currency rose against the US dollar.

The benchmark Korea Composite Stock Price Index shed 8.4 points, or 0.32 percent, to close at 2,577.12, ending its two-day winning streak, which had been fueled by an AI chip boom.

Trading volume was moderate at 670.12 million shares worth 14.61 trillion won ($11.01 billion), with losers outpacing gainers 558 to 303.

Seoul's stock market got off to a good start, with the Kospi touching an 11-month high of 2,596.31 at one point, before paring earlier gains and falling into negative territory.

Offshore and retail investors picked up a net 221.24 billion won and 62.48 billion won worth of shares, respectively, while institutional investors shed a net 287.96 billion won worth of shares.

Overnight, Wall Street closed mixed as the debt ceiling deal reached between US President Joe Biden and House Speaker Kevin McCarthy went to Congress.

The deal now needs to receive enough bipartisan support before the June 5 deadline to avert a potentially devastating federal default.

Earlier in the day, North Korea fired what it claims to be a "space launch vehicle" southward, in another event that might have shaken investor sentiment.

But Pyongyang's new Chollima-1 rocket carrying a military reconnaissance satellite crashed into the Yellow Sea due to the "abnormal starting" of the second-stage engine, according to its official Korean Central News Agency.

Large-cap issues finished mixed, with chip giants closing in negative terrain.

Tech heavyweight Samsung Electronics shed 1.24 percent to close at 71,400 won, and chip giant SK hynix declined 1.54 percent to 108,600 won.

Leading battery maker LG Energy Solution jumped 3.28 percent to 599,000 won, and Samsung SDI stayed put at 718,000 won.

No. 1 steelmaker POSCO Holdings lost 0.83 percent to 360,000 won, while POSCO Future surged 2.49 percent to 350,000 won.

Carmakers ended mixed, with top automaker Hyundai Motor declining 0.25 percent to 200,000 won and its affiliate Kia gaining 0.35 percent to 85,900 won.

Major bio firm Samsung Biologics climbed 0.77 percent to 784,000 won, while Celltrion lost 0.58 percent to 171,300 won.

The local currency ended at 1,327.2 won against the US dollar, down 2.3 won from the previous session's close. (Yonhap)