A Practice Note discussing hell or high water (HOHW) clauses, which require the buyer to do whatever is necessary to obtain antitrust clearance in M&A deals. This Practice Note discusses when to use an HOHW clause and what it obligates the buyer to do, alternative provisions used instead of an HOHW clause, and other antitrust risk-shifting provisions used with an HOHW clause. This Note includes links to What's Market summaries containing HOHW clauses as well as other antitrust risk-shifting provisions in certain public and private agreements. This resource will be updated annually.