It also triggered massive capital outflows from Europe. As much as US$6 billion has been withdrawn from European equities in a single week, according to data provider EPFR. The money has mainly flowed into the US and some emerging markets.
Certainly, sentiment has shifted in just a few weeks. While the City increasingly adopts the traditional European model of vacationing en masse in the summer, the warning signs have been picking up.
Immediately after the referendum, many ordinary investors lapped up the opportunity to buy oversold assets at rock-bottom prices.
UK, US and most Asian equity markets rose in the weeks immediately after the vote, with volatility only slightly elevated.
No one has as a clue how greatly the British economy will lose out in trade deals The rapid appointment of Theresa May brought stability to UK policy-making, and gilts rallied nicely, with their yield against Bunds and Treasuries narrowing rather than widening. Sentix research group's monthly index of investor morale rose to 4.2, from 1.7 in July, which seemed to indicate that Eurozone investors had shaken off their initial concern over Brexit.
However, there is a long negotiation process with the EU ahead, which will grind on, drag down growth and could prompt periods of sector- and industry-specific uncertainty.
No one yet has as a clue for how greatly - or even whether - the British economy will lose out in trade deals or face new barriers or tariffs.