The invention is directed to a liquid, aqueous formulation of coagulation Factor VIII, comprising a Factor VIII molecule, a calcium salt in a concentration of more than 10 mM, and a saccharide and/or polyol in a concentration of at least 100 mM, wherein the formulation has a pH from 5.5-7.5. The invention furthermore provides a method for optimising a liquid formulation of coagulation Factor VIII, the method comprising the steps of: (i) Providing one or more liquid formulations comprising Factor VIII to be tested (ii) Adding a protein denaturant to said liquid formulations, and incubating the resulting solutions for a predetermined period of time (iii) Analysing the incubated solutions of (ii) for the presence of dissociated Factor VIII and (iv) Selecting one or more formulation(s) having a desired low level of dissociated Factor VIII.
