Andrew Harrer/Bloomberg News

The Federal Reserve announced on Friday afternoon that it planned to hold hearings on Capital One Financial‘s proposed $9 billion takeover of the ING Group‘s online banking operations in America.

The move follows concerns that the deal would create a new too-big-to-fail giant. By buying ING Direct USA, Capital One would become the nation’s fifth-biggest lender, with more than $200 billion in deposits.

Earlier this month, Representative Barney Frank, Democrat of Massachusetts, asked the Fed to hold public hearings to gauge the deal’s potential effects on consumers and the public.

“Care should be taken to thoroughly examine the impact of this purchase with respect to the consolidation of banking assets, the provision of credit by the resulting bank and compliance with the Community Reinvestment Act,” Mr. Frank wrote in a letter to the Fed chairman, Ben S. Bernanke.

The Fed said that it planned to hold hearings in Washington, Chicago and San Francisco beginning Sept. 20. It will also extend the time that it will accept public comments on the deal until Oct. 12.

Several consumer groups, including the National Community Reinvestment Coalition, have already opposed the deal. Their argument is that Capital One — already considered a systemically important financial institution because it oversees more than $50 billion in deposits — would become an even bigger risk to taxpayers if it needed a bailout.

Capital One has argued that unlike such institutions as Goldman Sachs, it does not engage in risky trading. Its core business is credit card lending, an operation that would benefit greatly from the deposits it would gain from ING Direct.

The bank also contends that the ING deal would make it more stable, by reducing its reliance on short-term borrowing that could seize up in a financial crisis.

“We will remain a traditional bank with only 1.5 percent of deposits nationwide and none of the complexity that the Dodd-Frank reform bill addressed in ending ‘too big to fail,'” Capital One said in a statement late on Friday.

The firm added, “In each of our prior bank acquisitions, we have substantially increased our investments that serve lower-income communities, providing $2.2 billion over and above those predecessor banks in their footprints.”

Capital One has said that it expects the deal to close by the end of the year.