LESSON 1.5 · FOUNDATION

Why the price you saw isn't the price you got

Spread, slippage, and the seconds between click and fill.

FOUNDATIONS3 MIN READ

Every stock actually has two prices at once: the bid/ask spread — the highest price a buyer will pay (the bid) and the lowest a seller will accept (the ask). The single number you see quoted is usually a mid price, sitting between the two — not a price you can actually deal at.

Buy, and you pay the ask; sell, and you receive the bid. On a busy stock the gap is a rounding error; on a thin one it can be real money. Add in slippage — the price drifting between when you click and when the order actually reaches the exchange — and the fill you get can sit a little away from the quote you were looking at a second earlier.

Bid · £4.98Mid · £5.00Ask · £5.02

A 4p spread on a £5 stock — small, but never actually zero.

Compare your buy price to today's price →

Educational content only. It is not personal financial advice.