Shares of Aboitiz-led Union Bank of the Philippines (UBP) rose by 6.42 percent on Thursday as the bank confirmed reports that it's negotiating to take over the Philippine consumer banking assets of American banking giant Citi.

Commenting on reports that it's the "preferred bidder" for these Citi assets with an estimated value of $1 billion, UBP confirmed to the Philippine Stock Exchange the ongoing discussions with Citi, which is bowing out of the local consumer and retail banking businesses as part of a global downsizing program.

"The discussions between the bank and Citi are at preliminary state, and any transaction in relation to the foregoing would be subject to, among other things, the completion of satisfactory due diligence, the negotiation and execution of definitive transaction documents, satisfaction of the conditions contained therein and the approval by the regulars of the transaction," UBP said in its disclosure.

"Accordingly, there can be no assurance that the transaction will be completed at this stage," it added.