The City watchdog, the Financial Services Authority, is monitoring the health of banks much more assiduously than it was a year ago - and is assuring itself that each of them has enough capital to support their business plans.
That's one of the reasons why Royal Bank of Scotland has decided to raise a record-breaking £12bn of new cash from its shareholders in a rights issue.
Or to put it another way, the climate for banks has changed in a fundamental way.
It seems only yesterday it was all about growth and opportunities.
Today bankers have remembered - some would say belatedly - that there are risks associated with lending.
So Royal Bank has also announced that, on a permanent basis, it will retain more capital in its balance sheet to meet the risks of default by borrowers than it had been doing.
The bank's shareholders are not happy that it has had this awakening only after suffering record write-downs for a British bank (of £5.9bn before tax) on its investments and loans related to sub-prime and private equity (though they will, in the end, probably decide that the best punishment for the chief executive, Sir Fred Goodwin, is to insist he stay in place at least long enough to reap whatever incremental profits are available from the tricky job of integrating the sprawling international wholesale banking operations of the Dutch bank ABN, which Royal Bank acquired last year).
The scale of Royal Bank's humiliation is that it is raising an additional £4bn by selling businesses - including all or part of its substantial insurance operation - to cover those losses.
What about its big rivals? Are they too going to raise new equity capital through rights issues and disposals to reinforce their foundations?
None have quite the same urgent need as Royal Bank. But it would be slightly odd if Barclays and HBOS did not conclude that their advantage lies in pumping up their stock of capital earlier rather than later.
Why? Because in the new, scarier climate, the Financial Services Authority will allow them much greater latitude in pursuing their ambitions if they can swank that they are among the best capitalised banks in the world - and they can't boast that now.