When you own a Business before you Marry

If you own a business before marriage [separate], and if after marriage your personal efforts [community] increases the value of that business, then it becomes necessary to quantify the contributions of separate capital and community effort to the increase, because the community is entitled to the increase in profits attributable to the community endeavor.  

Brandes (2015) 239 Cal. App. 4th 1461, 1472.