SINGAPORE, June 1 (IFR) - Asian credits were holding up, despite weak Chinese economic data with investment-grade bonds tightening 1bp.

The Caixin/Markit manufacturing purchasing managers' index fell to 49.6 in May, below the 50.1 expected by economists and down from 50.3 in April.

Chinese stocks fell 0.5%, but the Hang Seng Index gained 0.5%, while the Nikkei ended 1% higher.

"We are seeing some buyers moving into the credit market, with a fair number being real-money guys," said one Singapore-based trader. The demand has shored up Asian credit prices.

Kookmin's five-year FRN, priced at 95bp over 3-month Libor in late May, was still hovering at 87bp/85bp, while ChemChina's 3.9% perpetual notes were robust at a cash price of 101.00/102.00, above reoffer at par.

Recently sold high-yield issues were also doing fairly well. ESR Cayman's smaller-than-expected perpetual notes stayed above water with offers at 100.50, while bids were heard around at par.

Melco's 4.875% 2025s were quoted at 100.75/100.97, while Dr Peng's 2019s were indicated at 100.875/101.25.

Reliance Communication's 6.5% 2020s were still under siege after Moody's rating downgrade with a quote of 67.00/70.00.

(Reporting by Kit Yin Boey; editing by Dharsan Singh)