Bank stocks were under siege Monday, for obvious reasons. On the off chance you haven’t noticed, there’s a mini-panic afoot in the US banking sector.

Over the weekend, I suggested repeatedly that although the Fed and Treasury did what they could, it wouldn’t prevent additional turmoil. And it didn’t.

Smaller banks were a veritable bloodbath. First Republic, Western Alliance and PacWest were trading like they’d already failed, for example.

The Monday wipeouts illustrated above all constituted record declines. Dick Bove called some of the price action “absolutely absurd.”

And maybe it is — “absurd,” I mean. But the mere specter of bank runs is terrifying, and as I put it over the weekend, “you can be absolutely sure that scores of opportunistic vultures spent their Saturday making hit lists of bank shares likely to come under pressure.”

KeyCorp is the 20th largest lender in the country. It too was under the proverbial gun.

If you’re keeping score at home, that’s a 40% wipeout in the space of a week. And it’s far from clear that it’s justified given the new Fed liquidity facility but, one more time: A panic is a panic. By definition, panics aren’t rational.

In a Monday note, Nomura’s Charlie McElligott walked through the factors weighing on bank shares. “Banks around the world are appropriately getting starched for a lot of reasons,” he wrote. Those reasons include:

• The unintended consequences of the new US depositor guarantees, as “deposit flight” risk may actually grow.
• The apparent lack of interest in buying-off some of the assets [could be] indicative of low bank risk-appetite and [may raise] further questions around regional bank loan portfolios.
• The implications for obvious NIM compression around an almost certain higher cost-of-capital for some banks.
• The broad industry will likely suffer too under wider credit spreads (bond holders are getting appropriately wrecked, after all).
• And perhaps most critically in the macro sense, a likely further downshift in lending / tighter standards which were already under way anyhow.

Charlie also suggested some banks may be forced to raise new capital. Depending on the bank, that might not be easy. Just ask SVB.

Commenting further on Monday, Bove said, “Every bank, of any size in the United States is going to be raising common equity in huge amounts over the next few month.

Meanwhile, David Chiaverini at Wedbush said it’s “ironic that we’ve had three bank failures in the past week despite not being in a recession.” In his view, ongoing pressure on deposits could presage “lower credit availability in the banking system,” which might in turn put the brakes on the economy.

In another social media post, Bill Ackman wrote that “Our economy will not function effectively without our community and regional banking system.” His solution: “The FDIC needs to explicitly guarantee all deposits now. Hours matter.”