Mr. Robbins said he supported measures to limit bailout money for executive compensation and buybacks. “Generally I would think that’s appropriate,” he said. “Those aren’t the problems we are solving for.”

Many economists say that the federal government risks catastrophe if it does not respond to the dimming economic activity by showering individuals and businesses with significant financial support. Lawmakers have already approved some expansions in unemployment benefits and mandated paid leave for many workers affected by the virus, and this week, they began to coalesce around plans to send direct payments to individuals across the country.

Agreement appears more elusive over the best way to help businesses, including how much to spend and what conditions to attach. But most parties agree there is little time to dicker over the details.

The crisis is hitting many low-margin, service-industry companies particularly hard, taking a bite out of small businesses that power much of the economy. Half of all workers are employed by companies with fewer than 500 staff members and small businesses exist in every congressional district around the country.

One proposal circulating on Wednesday among White House officials, including the conservative economists R. Glenn Hubbard and Michael R. Strain, called for banks to lend an estimated $1 trillion to small companies to help cover 12 weeks of missed revenue — and for the government to pay off the loans, provided the companies do not lay off workers.

Senators Marco Rubio, Republican of Florida, the chairman of the committee on small businesses, and Susan Collins, Republican of Maine, proposed a similar plan on Wednesday, which would cover six weeks of revenue and cost an estimated $300 billion.

“There is broad general agreement that small businesses in this country will not be able to survive unless there is extraordinary assistance,” Mr. Rubio said. “The goal is to keep employees connected to their employers, so that people aren’t just having to stay home and aren’t just feeling the stress of being laid off, but the uncertainty of whether they’ll even have a job to go back to.”