In the long list of nightmares that market risk managers have to wrestle with on a daily basis, some have gradually receded. For competently-run banks and large trading institutions, the possibility of a rogue trader making undiscovered trades or mis-marking his own book – another Nick Leeson – is increasingly remote given the layers of oversight. But one nightmare in particular has been increasing in frequency since 2009, especially as Volcker Rule and Dodd-Frank restrictions have been implemented.

The concern is market illiquidity. Every year that goes by, liquidity in the financial markets is declining. This is not apparent to the casual observer, or casual investor, who faces a tight market for his hundred- or thousand-lot. But probably every institutional investor has a story of how his attempt to hit a bid on the screens resulted in his trading the minimum size while the rest of the bid fled with sub-millisecond dispatch. And so the question is: if your mutual fund is hit by redemptions at the same time that its market (equities, emerging markets, credit?) is falling apart – and that is the normal time that redemptions swell – then at what price will it be able to get out? And what if there is no bid at all that is big enough?

Banks and other dealing institutions have responded to both the new regulatory restrictions themselves, and to the effects of the restrictions, by decreasing the size of their balance sheet dedicated to trading. Much of the apparent ‘liquidity’ in the market now is provided by the algos (the algorithmic trading systems) who as we have seen can be there and gone in an eyeblink. I am not aware of anything that has been done in the wake of the various “flash crashes” we have seen that would lead me to have great confidence that in the next big market discontinuity markets will function any better than they did in 2008. In fact, public liquidity is quite a bit smaller and I would expect them to function a fair bit worse.