Quote from Deviouz:
I think he is referring to what I said about how we'd change our quoting behaviour when prices start heading in one direction.
I wasn't specific enough, I meant when a shock enters the market, quotes will widen significantly or be pulled while we reassess what the news means, and then the quotes will be kept wider than before to account for the increased volatility. The main risk a market maker faces is from sudden shocks where traders can hit us at prices that are bad for us, ie. at prices that were fair before the shock and the future price has moved away such that we miss the hedge.
Generally if markets are heading down, the vols will be jammed up (leading to higher option prices), particularly on the downside. This is done to account for the increase in buying pressure. But despite the wider spreads, we generally don't quote any differently because we can always hedge (ie. we keep quoting around the fair price, we don't bias anything as if we were to expect further down movement in the future). These times are often when we are making the most money because of the higher credit we get from the bid/ask spread.