How Long Would It Take To Get Out?

A position that's easy to see on your risk report — a dollar amount, a number of shares — hides a second number that matters just as much: how long it would actually take to unwind it without your own selling driving the price down further. Two positions of identical dollar size can have completely different real risk if one trades in a market with enormous daily volume and the other trades in a name where your position is several days' worth of typical turnover. The size on the screen is the same. The exit is not.

Why this number gets ignored until it's needed

Under normal conditions, exit time rarely matters — the position is small relative to the market, you can get out in minutes if you want to, and the question never comes up. It becomes the only question that matters the moment you actually need to leave in a hurry, typically during exactly the kind of stressed market where liquidity has already thinned out and your position looks large relative to a smaller-than-usual daily volume. A rule of thumb used on many desks is to size a position against a fraction of average daily volume — often something like 10-20% — specifically so that even in a bad week, the position can be unwound over a handful of days without single-handedly moving the price.

A desk holding a position in a mid-cap name sized comfortably against a $2m daily risk limit discovered, when it needed to reduce risk during a broader market selloff, that the position represented nearly four days of the stock's now-thinned trading volume rather than the roughly one day it represented when volumes were normal. Selling it in one day would have meant accepting a materially worse average price than the position's marked value suggested, because the desk's own selling would have been a large share of that day's volume. Trimming over several days instead preserved most of the marked value but meant carrying the risk longer than planned — a tradeoff the desk hadn't priced in when the position was originally sized only against its dollar risk limit, without a separate look at exit time.

Exit time isn't a fixed property of a position; it shrinks in calm markets and grows in stressed ones, which is exactly when you're most likely to need to know it.