With less than two days until the outcome of the Brexit referendum, traders around the world know two things: in a scene reminiscent of Lehman Sunday, everyone will be ready to trade the nanosecond the first results are released resulting in a supernova of volatility and an unprecedented burst in volume or... markets will simply grind to a halt as banks refuse to take risk positions and execute client orders, all bids and offers are withdrawn as the last trace of liquidity evaporates, and central banks are forced to start trading with each other in the open market.
As the following just released warning from UBS to its clients reveals, it will probably be the latter, to wit:
Regardless of the outcome, we may see an increase in volatility and an impact on trading volumes. In the event that extreme market moves occur in an environment of limited liquidity, our principal spreads may widen for both electronic and voice trading, liquidity may reduce and prices may turn indicative (i.e., non-tradable) for periods of time.
Full UBS email.