Bid Price

The bid is the price at which you can sell immediately, which makes it — not the last traded price — the honest valuation of a holding you might need to exit. There is a bid at every price level below the best one, and the quantity stacked at each level is the market's depth on the buy side. When a stock is falling, bids are withdrawn faster than they are replaced, so the visible bid can be much thinner than the average day suggests. Beginners often read the bid as 'the price' and are then surprised that selling gets less than the screen quoted.