BlackRock found itself in a similar situation during the last crisis. After Bear Stearns and American International Group collapsed, the New York Federal Reserve retained BlackRock to help oversee billions of dollars in ailing assets that had belonged to them. The firm helped price and sell those assets for the government at the same time it was helping private clients buy similar assets.

At the time, that arrangement prompted criticism from lawmakers and others who worried about coziness between Wall Street and Washington, as well as the potential for conflicts of interest.

“The key here is for the Fed to avoid the backlash like last time,” said Dennis Kelleher, president of Better Markets, a nonprofit group that supports stringent financial regulation. “The Fed needs to guarantee there is full transparency and oversight of BlackRock.”

BlackRock’s dominant position in the stock and bond markets — and, with it, its influence over Wall Street — has only grown in the past decade. The firm now manages nearly $7 trillion in assets for big private clients, including pension funds, hedge funds and sovereign wealth funds. It managed about $1.3 trillion at the time of the last crisis.

The Fed has not yet posted a copy of the contract it signed with BlackRock, though it plans to disclose more details. The central bank was slow to disclose the specific terms of its agreement with BlackRock during the last crisis, and even today the full details of what the firm earned have not been disclosed.