SEOUL (Reuters) - South Korea's factory output unexpectedly fell in September on weaker chip production, government data showed on Thursday.

The industrial output index fell 0.2% over the month on a seasonally adjusted basis, according to Statistics Korea, after a rise of 4.4% in the prior month, which was the fastest in a year.

The fall came against the median forecast of a 1.2% rise in a Reuters poll of economists.

Production of semiconductors fell 2.6%.

The index fell 1.3% on a year-on-year basis, compared with gains of 3.8% the month before and 0.8% expected by economists. It was the first annual decline since July 2023.