Thispaperinvestigatesthelead-lagrelationshipbetweenthestockindexfutures(knownasFKLI)anditsunderlyingindex,theKualaLumpurCompositeIndex(KLCI)intheemergingMalaysianmarket.Using15-secondintervaldata,cross-correlation,andthepartialadjustmentmodel,wefindabi-directionalasymmetriclead-lagrelationshipandthattheKLCI’sleadoverFKLIismuchstronger.TheevidencealsosuggeststhattheKLCIreturnsover-reacttoinformation,moresooncethintradingeffectsareconsidered.Overall,theevidencessuggestthattradersprefertoexploitstockspecificinformationintheunderlyingmarketdespitetheadvantagesoftradingtheindexfutures.