Jefferies inserted a $4 million break-up fee in an offer contract and wants it to be paid.Epic Cure/ShutterstockJefferies included a $4 million break-up fee in an offer letter to a banker.The Wall Street bank is demanding payment after Dean Decker stayed with Credit Suisse after signing.A California appeals court is expected to rule shortly on whether the break-up clause was legal.A Wall Street bank inserted a $4 million break-up fee into an offer letter and demanded the payment after the employee backed out.