Core terms
Scalping (stock trading style)
A trading style of very short holds, from seconds to a few minutes, aiming for a few cents to a few tens of cents per share. Costs, fills and flat outcomes make up a large part of each result.
Scalping describes a holding period and a cost structure, not an entry method. Any setup can be traded as a scalp or as a longer day trade; what changes is the arithmetic. Traders call the individual trades "scalps", "base hits" or "in-and-out trades".
With small targets, per-share costs become a large share of each gain. On a 10-cent target at 1,000 shares, $5.00 of round-trip costs is 5% of the gross win; on a 50-cent target it is 1% (Illustrative). Stop slippage and scratches that still pay the spread and fees weigh in the same way.
Other meanings
In securities law, "scalping" names an unrelated fraud: an adviser recommends a security they hold, then sells into the price move the recommendation causes. The word is also used for ticket resale. Neither is the trading style.
What traders should verify
Write the planned holding time, target and stop in cents, and the cost per round trip, before trading a plan as a scalp. Group results by style so scalps and longer holds are not averaged together.
Do not conflate
Trader usage; there is no official definition. Holding-time ranges for "scalping" vary between sources, and a short hold does not limit the size of a loss: a halt or gap can fill a stop far from its price. Search results also mix in adviser scalping, the securities-fraud sense addressed in *SEC v. Capital Gains Research Bureau* (1963).
Primary source
Trader usage: there is no official definition, and platforms and tools may calculate it differently.