Market makers talk about inventory risk: holding a position you didn't really want. Retail scalpers have a version of it too, and I've been caught by it.
How it happens:
Adding to a position "because it's a better price now".
A limit order fills, then another, on related pairs, and suddenly you're long USD three times.
Partial exits fail and you're holding more than intended.
Pending orders you forgot about trigger during news.
The real problem is that each trade looks fine on its own. The total exposure isn't.
What I do:
A maximum total risk on all open positions: 1% of account, no matter how many trades.
Currency exposure check before each new entry: if I'm already long USD through EURUSD short, I don't add a USDJPY long.
All pending orders cancelled at the end of each session.
No averaging into losers. Ever.
The worst loss of my last year came from three correlated positions that each risked 0.5%. Together they lost 1.4% in a few minutes. Each trade was "within rules".
Do you have a rule for total exposure, or do you just track risk per trade?
A market maker doesn't just quote the fair price. It quotes a price shaded by its own position. A dealer long too many euros will lower its bid and offer slightly, making it more attractive to buy euros from it and less attractive to sell more to it. The skew can be tiny, a fraction of a pip, but it's real.
Scalpers feel the effect without seeing it. A pair that seems to hang slightly below or above where other sources say the price should be might be reflecting one large provider's inventory. The aggregated price on a retail feed is built from several of them, and the one with the strongest lean can drag the composite.
It also explains some odd behaviour after big client flow. A large buy order gets filled by a dealer, who then needs to offload the position. Over the next several minutes, the dealer's quotes lean to encourage selling, and price can drift in the opposite direction of the original trade without any news.
Inventory management is part of why short-term price movements often reverse partially. The initial push comes from a client order, and the reversal comes from the dealer rebalancing.
For a scalper, the practical message is caution about assuming that every move has a reason. Some are just risk transfer, and they fade as soon as the inventory is cleared.
Reading it directly is impossible without privileged data. The footprints show up as small, persistent drifts against recent order flow, with no obvious trigger.
Treating a sharp, unexplained move with some suspicion, and giving it a few seconds to settle, often beats jumping in.
Has an apparently unexplained drift ever turned out to be the aftermath of a big order?
