A Practice Note discussing terms that address litigation obligations in purchase and merger agreements for transactions that may raise antitrust concerns. This Practice Note discusses the types of litigation obligations that merging parties can negotiate, such as an unconditional obligation to contest and defend any litigation challenging the transaction, or limitations on that obligation, such as only litigating if doing so would not result in a material adverse effect, or no obligation to litigate. It also discusses other antitrust risk-shifting provisions used with litigation obligation provisions, such as divestiture obligation provisions and reverse break-up fees. This Practice Note includes links to What's Market summaries of antitrust risk-shifting provisions in certain public and private agreements.