The Smart Way to Acquire or Merge into an Ohio Business and the Difference Between an Asset Purchase Agreement and a Stock Purchase Agreement. Utilize our Stock Purchase Agreement (SPA) to officially document the stock purchase, ensuring the protection of both the buyer and seller.STOCK PURCHASE AGREEMENT from STERIS CORP filed with the Securities and Exchange Commission. I'm gonna break down all the terms and conditions so you can understand what it means and we're gonna fill that out so you can have a real-life example of it. A stock purchase agreement is a legal contract that governs the sale and purchase of shares in a company, specifying the transaction's terms and conditions. In a stock purchase, the buyer purchases the entire company, including all assets and liabilities. This article will discuss the various contractual elements contained in all real estate purchase agreements and the issues that arise therefrom.