Regulators have told Bank of America Corp Chief Executive Brian Moynihan and other executives that the largest U.S. bank by assets must become much smaller, Fox Business Network's Charlie Gasparino reported on Wednesday.

Industry overseers are increasingly concerned about U.S. banks being too big to fail, according to the report on Fox Business Network's website.

The regulatory focus on Bank of America comes as Citigroup Inc, now the third largest U.S. bank, has announced a plan to shrink the company, and has shed hundreds of billions of dollars of assets since 2007, Gasparino reported.

In an email to Reuters, Bank of America spokesman Scott Silvestri wrote, We are comfortable with our integrated banking model as it exists today and don't see any likely outcome to the regulatory reform discussions that would significantly affect our ability to keep operating as we are today.

Bank of America has $2.2 trillion in total assets as of December 31, 2009, according to the company's fourth quarter earnings report.

A plan to shrink Bank of America would be complicated by the fact it is unclear what assets it could sell, the Fox Business Network report states.

Earlier on Wednesday, Moynihan told investors and analysts at the Citigroup Financial Services Conference that the company had the ability to grow, and it would only focus on divesting smaller, ancillary business units in the coming months.

Moynihan, during the conference, cited pending deals to sell Columbia Asset Management's operations to Ameriprise Financial Inc and First Republic bank to a private equity group as examples of the bank's deals going forward.

Both units were viewed as extraneous by analysts after Bank of America purchased Merrill Lynch in January 2009.

(Reporting by Joe Rauch; editing by Carol Bishopric)