With the increasing number of mergers and acquisitions during the last two decades, the letter of intent, which precedes most forms of acquisitions of businesses, has become a widespread tool and, indeed, is often considered as a sine qua non condition of any merger or acquisition (M&A). Nevertheless, this institution still enjoys — or suffers from — an almost total absence of specific regulation in Swiss law, while its purpose, nature and effects are often uncertain and misunderstood.