HONG KONG, May 16 (IFR) - Asian credits traded slightly tighter on Tuesday as regional stock markets generally took their cue from an overnight rise in the US. New issues were active with four issuers marketing new US dollar notes and a few announcing mandates.

The iTraxx Asia investment-grade index tightened less than 1bp at 87.6/88.9.

Investment-grade credits in general tightened 1bp-2bp, with ICBC Dubai branch's newly issued two-tranche US dollar bonds actively traded, according to a Hong Kong-based trader.

ICBC Dubai's 3-year floaters were 2bp tighter while its 5-year floaters were 1bp tighter from reoffer levels of three-month Libor plus 77bp and 87bp, respectively.

China Oil & Gas's 2022s traded up and were quoted at 100.05/101.10 as oil extended gains after Saudi Arabia and Russia supported an extension of producer supply cuts into 2018.

Noble Group's 2022s fell around 2 points to 49.67/52.33. Moody's last night cut the commodity trader's corporate family rating and senior unsecured bond ratings to Caa1 from B2.

Biostime's 2021s were flat at 104.625/105.625 after a sell-off on Friday.

S&P said today that the Chinese infant milk formula provider's BB rating and stable outlook were not immediately affected by the existence of options that could lead to an eventual takeover of a fast-growing business franchise in China.

"We believe that Biostime's good operating cashflow and disciplined capital spending will temper the impact from PGT's potential exercise of the options in or after September 2020," said S&P.

(Reporting by Carol Chan; Editing by Vincent Baby)