Business optimism in South Korea's manufacturing and services sectors remained tepid in October, the Bank of Korea reported on Wednesday.

The nation's composite business sentiment index (CBSI) for all industries in October logged at 90.6, down from 91.6 in September, and slipping further below the 100-mark that separates optimism from pessimism, reported the central bank.

However, the October outlook for November inched up to 91.1, rising from 88.5 in September, added officials.

In the manufacturing sector, the CBSI for October posted at 92.4, down from 93.5 in September, while the outlook index for the following month rose to 92.6 from 89.4, added the Bank of Korea.

In the nation's non-manufacturing sector, the CBSI for October was 89.5, down from 90.5 in September, but the index for the outlook for the following month rose to 90.2 from 87.9.

South Korea's economic sentiment index (ESI), a composite of CBSI and the Consumer Survey Index (CSI), logged at 94.4 in October, up from 91.3 in September, according to official figures.

The Bank of Korea asked about 15 items, including business conditions, sales and profitability at 3,524 surveyed companies, to compose the CBSI.

South Korean enterprises are operating in a slow-growth economy.

The nation's gross domestic product (GDP) rose by 1.7% on year in the third quarter, and by 1.2% from the second quarter, reported the Bank of Korea on Tuesday.