Under half an hour, depending upon where the boomers may be. But I've been reassured by HN that MAD is no longer a thing: https://news.ycombinator.com/item?id=24662277

(Then again, assuming attacks these days are more likely economic than kinetic, it looks like it took two months, May-July 1997, to take down THB. The longest market manipulation of which I am aware lasted 5 years, but those were only a pair of billionaires, so presumably trillionaires' poker played between nation states might go longer until someone folds.)