The business sentiment of South Korea's private sector improved slightly in June, but pessimism about the future continues to persist.

According to the Bank of Korea on Thursday, the business sentiment index(BSI) for all industries came to 74 this month, up one point from a month earlier. 

A reading below 100 means pessimists outnumber optimists. 

The index posted 69 in January and February, and has been hovering between 73 and 74 since. 

South Korean manufacturers' sentiment decreased one point to 75 this month, while the BSI for non-manufacturing sectors gained three points to 74.

Local companies' outlook for all industries for next month was 75, a two point rise from the previous month.