A Standard Clause that may be used in a purchase or merger agreement where a seller or target company wishes to include a provision requiring the buyer to pay a fee, known as a reverse break-up fee, in a transaction with antitrust risk. This fee is payable if the buyer terminates the agreement based on an antitrust-related event or trigger, such as the failure to obtain antitrust approval under the Hart-Scott-Rodino Act (HSR Act). This Clause discusses common antitrust-related triggers for reverse break-up fees and the value ranges for those fees. This Standard Clause has integrated notes with important explanations and drafting and negotiating tips.