Start with an identity that disposes of the naive reading: in a derivatives market, longs and shorts are exactly equal. Every contract has both sides. The market cannot be net long.
So any published ratio is counting something narrower — usually the number of accounts on each side, sometimes the number of positions, sometimes only the top accounts by size, always on a single venue.
Why accounts and exposure diverge
Ten small accounts long and one large account short can be a ratio of 10:1 long while the money is evenly matched, or net short in size. The ratio describes participant headcount, not capital.
That is not a flaw as long as you read it as what it is: a rough sentiment measure over a venue’s retail base. It becomes wrong the moment it is described as market positioning.
The venue problem again
Different venues serve different participants, so the same coin can show opposite ratios at the same moment — and each is correctly reporting its own users. This is precisely the reason funding is kept per venue, and the same discipline applies here.
What to use instead
For positioning, funding is the better instrument, because it is a price: it reports what one side is willing to pay, which weights by conviction and capital rather than by headcount. For the size of the leveraged position, open interest is the measure, since it counts contracts rather than people.
The long/short ratio’s honest use is narrow: a rough read on whether a venue’s retail base is leaning, useful in combination and thin on its own.