Bret Devereaux

I'm not sure we should regard the affair as a major crisis. Dio gives it literally only a sentence (58.21.5) and thinks it mainly important because it resulted in the death of a notable equestrian by suicide before Tiberius bails everyone out.

I disagree. The historian Charles Bartlett called it a "severe economic crisis", and every financial and economic historian I have read on the subject thought it was a serious financial crisis. Perhaps it takes people with banking experience or knowledge of financial history...

to recognize how familiar the sequence of events were, beginning with years of capital outflows prior to the crisis. At any rate if this were only a minor event, it is hard to imagine why Tiberius, someone not famously liberal with his money, would have made such...

...a large, interest-free, 3-year loan to bankers when loans at the time were rarely extended for more than a few months. This was unprecedented, and was unlikely to be a response to a minor matter.

It was not unprecedented. Tiberius' two immediate predecessors, Julius Caesar and Octavian had made similarly sized donations to either the people of Rome, the public treasury, or both.

Octavian (Augustus) is at pains to point out that he made similarly massive donations to the public (RG 15) and that he bailed out the public treasury no less than four times, at a number significantly greater than what Tiberius spent (RG 17)

I suppose at some point it depends here on what we understand as a major crisis - evidently significant enough to drag in the emperor...but mostly because its consequences were confined to the landholding elite that dominated Roman politics.

I think the relative weight the sources give to it compared to the Sejanus affair - which occurs immediately prior in Tacitus and Dio (and chronologically) is illustrative. It is essentially a footnote in the back few years of Tiberius' reign.