Michael S. Barr, the Federal Reserve’s vice chair for supervision, introduced on Monday that he could be pushing for vital modifications to how America’s largest banks have been overseen in a bid to make them extra resilient in instances of bother — partly by ratcheting up how a lot capital they need to get them via a tough patch.

The overhaul would require the biggest banks to extend their holdings of capital — money and different available property that could possibly be used to soak up losses in instances of bother. Mr. Barr predicted that his tweaks, if implement, could be “equal to requiring the biggest banks maintain a further two share factors of capital.”

“The great thing about capital is that it doesn’t care in regards to the supply of the loss,” Mr. Barr stated in his speech previewing the proposed modifications. “Regardless of the vulnerability or the shock, capital is ready to assist take up the ensuing loss.”

Mr. Barr’s proposals should not a completed deal: They would want to make it via a notice-and-comment interval — giving banks, lawmakers and different events an opportunity to voice their views. If the Fed Board votes to institute them, the transition will take time. However the sweeping set of modifications that he set out meaningfully tweak how banks each police their very own dangers and are overseen by authorities regulators.

“It’s positively meaty,” stated Ian Katz, an analyst at Capital Alpha who covers banking regulation.

The Fed’s vice chair for supervision, who was nominated by President Biden, has spent months reviewing capital guidelines for America’s largest banks, and his outcomes have been hotly anticipated: Financial institution lobbyists have for months been warning in regards to the modifications he may suggest. Midsize banks particularly have been outspoken, saying that any improve in regulatory necessities could be expensive for them, reining of their capacity to lend.

Monday’s speech made clear why banks have been frightened. Mr. Barr desires to replace capital necessities primarily based on financial institution danger “to raised mirror credit score, buying and selling and operational danger,” he stated in his remarks, delivered on the Bipartisan Coverage Middle in Washington.

As an illustration, banks would not have the ability to depend on inside fashions to estimate some kinds of credit score danger — the prospect of losses on loans — or for notably tough-to-predict market dangers. Past that, banks could be required to mannequin dangers for particular person buying and selling desks for specific asset lessons, as a substitute of on the agency degree.

“These modifications would elevate market danger capital necessities by correcting for gaps within the present guidelines,” Mr. Barr stated.

Maybe anticipating extra financial institution pushback, Mr. Barr additionally listed present guidelines that he didn’t plan to tighten, amongst them particular capital necessities that apply solely to the very largest banks.

The brand new proposal would additionally attempt to deal with vulnerabilities laid naked early this yr when a sequence of main banks collapsed.

One issue that led to the demise of Silicon Valley Financial institution — and despatched a shock wave throughout the midsize banking sector — was that the financial institution was sitting on a pile of unrealized losses on securities categorized as “obtainable on the market.”

The lender had not been required to depend these paper losses when it was calculating how a lot capital it wanted to climate a tricky interval. And when it needed to promote the securities to lift money, the losses got here again to chew.

Mr. Barr’s proposed changes would require banks with property of $100 billion or extra to account for unrealized losses and beneficial properties on such securities when calculating their regulatory capital, he stated.

The modifications would additionally toughen oversight for a wider group of enormous banks. Mr. Barr stated his extra stringent guidelines would apply to corporations with $100 billion or extra in property — reducing the edge for tight oversight, which now applies essentially the most enhanced guidelines to banks which are internationally lively or have $700 billion or extra in property. Of the estimated 4,100 banks within the nation, roughly 30 maintain $100 billion or extra in property.

Mr. Katz stated the enlargement of powerful guidelines to a wider set of banks was essentially the most notable a part of the proposal: Such a tweak was anticipated primarily based on remarks from different Fed officers just lately, he stated, however “it’s fairly a change.”

The financial institution blowups this yr illustrated that even a lot smaller banks have the potential to unleash chaos in the event that they collapse.

Nonetheless, “we’re not going to know the way vital these modifications are till the prolonged rule-making course of performs out over the following couple of years,” stated Dennis Kelleher, the chief govt of the nonprofit Higher Markets.

Mr. Kelleher stated that on the whole Mr. Barr’s concepts appeared good, however added that he was troubled by what he noticed as an absence of urgency amongst regulators.

“In relation to bailing out the banks, they act with urgency and decisiveness,” he stated, “however in relation to regulating the banks sufficient to forestall crashes, they’re sluggish and so they take years.”

Financial institution lobbyists criticized Mr. Barr’s announcement.

“Fed Vice Chair for Supervision Barr seems to imagine that the biggest U.S. banks want much more capital, with out offering any proof as to why,” Kevin Fromer, the chief govt of the foyer group the Monetary Companies Discussion board, stated in a press release to the information media on Monday.

“Additional capital necessities on the biggest U.S. banks will result in greater borrowing prices and fewer loans for shoppers and companies — slowing our economic system and impacting these on the margin hardest,” Mr. Fromer stated.

Susan Wachter, a finance professor on the College of Pennsylvania’s Wharton Faculty, stated the proposed modifications have been “lengthy overdue.” She stated it was a aid to know {that a} plan to make them was underway.

The Fed vice chair hinted that further financial institution oversight tweaks impressed by the March turmoil have been coming.

“I will probably be pursuing additional modifications to regulation and supervision in response to the current banking stress,” Mr. Barr stated in his speech. “I anticipate to have extra to say on these matters within the coming months.”