UPDATE 1-BAY delays signing deal for HSBC's Thai retail unit-source

* Delay is mainly due to document process

* Bank of Ayudhya is due to announce 2011 earnings Jan 20

* Analysts positive on bank's retail business outlook

* Shares up 1 pct, outperform market

By Manunphattr Dhanananphorn

BANGKOK, Jan 17 (Reuters) - Bank of Ayudhya, Thailand's fifth-largest lender, will delay to the end of January from this week plans to sign a deal to buy HSBC's Thai credit card and retail business, a senior official at the bank said.

The delay was mainly because the Thai bank, part-owned by General Electric, needed more time to prepare some documents, said the official, who declined to be named but is close to the deal.

The source did not give a value for the deal, but HSBC's retail business has a loan portfolio of about 30-40 billion baht ($942 million to $1.26 billion) and about 500,000 credit card customers.

"The signing will be postponed to the end of this month because we have to prepare some documents while waiting for the other side (HSBC)," the official said, adding it's certain for Bank of Ayudhya to be the successful suitor despite the delay.

Siam Commercial Bank was also interested in the HSBC operations, sources close to the deal said in December.

The deal, subject to approval from the Bank of Thailand, is part of a drive by Bank of Ayudhya to expand its retail services and comes after HSBC announced that it intended to quit businesses or countries where it lacked scale.

ANALYSTS OPTIMISTIC

Bank of Ayudhya, 33 percent owned by a unit of General Electric, has said it was looking to buy assets to boost its leading share in the retail market, including personal loans and credit cards.

Analysts are optimistic about Bank of Ayudhya's retail banking business, citing growth in domestic consumption could be boosted by post-flood demand for rehabilitation and the government's stimulus policies.

"BAY has a promising platform for retail banking, setting it up as a genuine candidate for playing the domestic consumption theme," Monchai Jaturanpinyo, analyst at CIMB Securities, said in a note.

Bank of Ayudhya has about 4 million credit card customers and a retail loan portfolio of about 70 billion baht ($2.2 billion).

The bank is due to report its 2011 earnings on Friday and has no plan to give details about the acquisition during the press conference on the same day, the official said.

Bank of Ayudhya is expected to report a 2011 net profit of 11.2 billion baht versus 8.79 billion in 2010, according to Thomson Reuters I/B/E/S.

At 0430 GMT, Bank of Ayudhya shares were up 1 percent, while the broader index was 0.6 percent higher.