Private equity firms Carlyle Group Inc and KKR are the top bidders for U.S. credit card issuer Discover Financial's $10 billion U.S. student loan portfolio, the Financial Times reported on Thursday.

The two are "working together" for the bid as private investment firms seek to expand their appetite for credit, the newspaper reported.

The report did not specify in what capacity the two firms were working together.

Other PE firms such as Ares, Blackstone, Brookfield, Fortress and Oaktree had also studied bids for the loan portfolio, FT said.

Discover Financial, Carlyle, KKR, Ares, Blackstone, Brookfield, Fortress and Oaktree did not immediately respond to Reuters requests for comment.

FT added that the deal is likely to conclude later this month or in early July.

Last November, Discover Financial said it was exploring the sale of its student loan portfolio, stating that a potential sale would see the servicing of these loans transferred to a third party.

Earlier this year, Warren Buffett-backed U.S. consumer bank Capital One said it would acquire Discover Financial for $35.3 billion in an all-stock deal.

The deal comes as regulators ramp up scrutiny of bank mergers under U.S. President Biden's administration, and as debate over the risks and benefits of bank mergers intensify after JPMorgan and New York Community Bank NYCB.N were allowed to snap up failed bank assets last year.

(Reporting by Gursimran Kaur in Bengaluru; Editing by Janane Venkatraman )