Crosspurchase agreements are agreements where business owners purchase a departing owner's interest in the business. The general rule is that contracts are freely assignable and can be transferred from one party to another.There are, however, exceptions to this general rule. Sell agreement is a contract between different entities within a corporation to buy out the interests of a deceased or disabled member. A business purchase agreement is a legal contract specifying terms for buying or selling a business, including conditions and obligations. Sell agreement is a legally binding document between company shareholders. A structured guide with worksheets to assist you in the development of your business plan, financial projections, and operating budget. Page 2. Massachusetts.