Inhibits factor X (X(a)) directly and, in a Xa-dependent way, inhibits VIIa/tissue factor activity, presumably by forming a quaternary Xa/LACI/VIIa/TF complex. It possesses an antithrombotic action and also the ability to associate with lipoproteins in plasma. This inhibitor contains three inhibitory domains. The first domain interacts with VIIa and TF, the second one with Xa (By similarity). O-glycosylated.