SE Asian Stocks-Vietnam jumps on inflation outlook;Thai down

* Expectation of slower inflation lifts Vietnam stocks

* Thai and Singapore drop, led by banks, telecoms

* Indonesian banks end higher

By Harry Suhartono

JAKARTA, Sept 22 (Reuters) - Stocks in Vietnam rose 4.7 percent on Monday led by consumer-related and commodities shares, thanks to an improving inflation outlook, while Singapore fell as investors sold bank stocks after last week's short bounce.

Thai shares .SETI lost 1.7 percent, with mobile phone operator Advanced Info Service ADVA.BK down 5.7 percent and Total Access Communication DTAC.BK losing 1.8 percent.

"Foreign investors have been buying Thai stocks since Friday but they were mainly for covering their short positions. They are now selling again, and banks and telecoms are their targets" said Pichai Lertsupongkij, head of sales at Thanachart Securities.

"Market players are cautious in response to weak global equities, while they are watching details about financial bailout plans."

Asian stock markets rose after more details about the U.S. government's $700 billion crisis solution encouraged bargain hunting, but questions lingered about long-term implications and the economic outlook. [ID:nHKG105506]

Vietnam's Ho Chi Minh Stock Exchange index .VNI had its biggest daily gain since March 2008, following the government's comment that inflation in September would slow. [ID:nHAN94467]

Vietnam's Lam Son Sugar Corp LSS.HM, Petrolimex International Trading Co PIT.HM, and Interfood Co IFS.HM all advanced 5 percent.

Indonesian banks also rose, thanks to the coordinated move by the central bank and the finance ministry to boost liquidity to the sector. [ID:nJAK166611]

Indonesia's PT Bank Rakyat Indonesia Tbk (BBRI.JK) gained 5.4 percent while PT Bank Mandiri Tbk (BMRI.JK) jumped 4.7 percent.

Singapore's Straits Times index .FTSTI fell 0.6 percent, dragged by a 2.2 percent drop in Singapore Telecommunications (STEL.SI) and a 1.8 percent fall in bank UOB (UOBH.SI). (Additional reporting by Viparat Jantraprapaweth; Editing by Sara Webb and Anshuman Daga)