CIMB Bank launched a Facebook banking app in mid-December that lets customers transact with friends.

The app, called OctoPay, has three main functions: transfer funds from users' CIMB Bank and CIMB Islamic deposit accounts to OctoPay friends with either of those accounts; transfer funds to reload prepaid mobile phone accounts; and invite friends to contribute to a savings goal and share money online, said the company in an announcement.

OctoPay is an extension of CIMB Clicks, an internet banking portal that has a total of 3.6 million registered users in Malaysia.

"With OctoPay, we took the lead by diversifying our alternate delivery channels, and integrating our internet banking capabilities with social networking elements, which is convenient and fun for our customers who are also active Facebookers," said Renzo Viegas, group deputy chief executive officer and head of consumer banking, CIMB Bank, in a statement.

CIMB Bank, which has more than 1.3 million Facebook fans, serves as the CIMB Group's consumer bank and corporate banking franchise in Malaysia, Singapore and Cambodia.

Financial institutions in the U.S. have largely stayed away from offering customers the ability to transact in social media to date.

Vantage Credit Union, a Missouri based credit union, offers members the ability to do some of their banking via Twitter. The service, called tweetmymoney, has been available since 2009.