Chen v. Chen, 142 Wis. 2d 7, 416 N.W.2d 661, 665 (Wis. Ct. App. 1987) held that the employee spouse failed to rebut the presumption because the stock option agreement stated that the options were intended to reward past contributions to the employer and to induce continued employment. Id. The court stated that "it would be mere conjecture to attempt to separate the portion of the net profits attributable to [the employee spouse's] post-divorce efforts" because the increase in value was due, in part, "to market forces and innumerable other variables." Id.