Barclays Capital, Citigroup Inc. (C) and Credit Suisse Group (CS) have committed $2 billion in financing to back BlackRock Inc.'s (BLK) purchase of Barclays Global Investors business, according to several people familiar with the transaction.

BlackRock last week reached an agreement to buy the indexing giant from U.K. bank Barclays PLC (BCS) for $13.5 billion. The deal creates a money-management giant roughly twice the size of its closest competitor.

The financing is structured as a 364-day revolving credit facility, which is expected to be refinanced at a later stage through proceeds from debt offerings as well as any capital raising efforts, one of the people said.

The transaction, which is expected to close in the fourth quarter, gives Barclays a 19.9% stake in BlackRock. As a result, Barclays is providing the bulk of the $2 billion revolver, this person said.

Another person said that Barclays would stump up $1.2 billion of the total amount, with Citigroup and Credit Suisse providing the remainder. Both Citi and Credit Suisse acted as lead financial advisers to BlackRock.

So far only these three banks have committed to the financing, but their final exposures could be lower than their original commitments because more institutions are expected to join if the loan is syndicated, the first person said.

A spokesman for BlackRock wasn't immediately able to comment on the financing.

The transaction is subject to approval by Barclays shareholders and regulators.

   -By Kate Haywood, Dow Jones Newswires; 212-416-2218; kate.haywood@dowjones.com

(Carol Dean in London contributed to this report.)