**A demanding Shinnecock Hills layout (par 70, 7,440 yards) and the historical rarity of U.S. Open playoffs underpin the 73.5% implied probability for no playoff.** The course, hosting its sixth U.S. Open, rewards precision and course management in firm, fast conditions with thick rough and undulating greens—similar to the 2018 setup where Brooks Koepka prevailed at +1. This setup typically produces spread-out leaderboards rather than ties after 72 holes. No playoff has occurred since the 2008 18-hole Monday playoff (Tiger Woods def. Rocco Mediate); the two-hole aggregate format introduced in 2018 has yet to be triggered. A deep 156-player field featuring top-ranked players such as Scottie Scheffler, Rory McIlroy, and Jon Rahm further reduces tie likelihood, as elite ball-strikers and iron players tend to separate on this style of test. With the event starting June 18, current trader consensus reflects the low historical frequency and the course’s bias toward decisive outcomes over aggregate ties.