KKR & Co LP, one of the largest private equity firms in the world, made a $40 million follow-on equity investment in United Envirotech Ltd, showing great confidence in the huge Chinese water treatment market.

KKR is offering S$0.50 ($0.40) for each share of the Singapore-listed recycling and water treatment company, which focuses on the Chinese market. The offer represents an 8.5 percent premium to the volume weighted average share price for the past 30 trading days, the two companies said in a statement.

At that price, the $40 million investment would give KKR a stake amounting to 20.6 percent of the issued shares, according to Thomson Reuters' data.