Fill Ratio

Fill ratio, also called fill rate, is the share of submitted orders that are actually executed rather than rejected or cancelled. It is a practical measure of execution quality: a price stream may look attractive, but if a meaningful portion of the orders sent against it come back unfilled, the advertised quote is worth less than it appears. Fill ratios tend to fall during economic releases, at rollover and in fast markets, when providers pull quotes or apply last look checks. Traders usually read fill ratio together with average slippage and rejection reasons, since a high fill ratio achieved by executing orders at consistently worse prices is not automatically the better outcome.