Asked about the report, BlackRock spokesman Ryan O'Keeffe said in a telephone interview that "Philipp has no formal involvement in these discussions at all."

Hildebrand, who joined New York-based asset manager BlackRock in 2012, previously chaired the governing board of the Swiss National Bank. According to his biography on BlackRock's website, in that capacity he also was a member of the Financial Stability Board, where he was appointed vice chairman in 2011.

Sources have told Reuters that UBS was mulling a takeover of embattled peer Credit Suisse, which could allay fears that an unfolding crisis at the latter bank could destabilize the global financial system.

Earlier on Saturday, BlackRock said it has no plans or interest in acquiring Credit Suisse, after a report it was working on a bid to counter UBS.

(Reporting by Ross Kerber in Boston; Editing by Nick Zieminski)