U.S. soybean exporters are facing a sharp contraction in sales to their largest customer, China, as buyers there increasingly turn to Brazilian supplies. Year-to-date shipments to China are almost 50% lower than a year earlier, according to U.S. Department of Agriculture figures, erasing a key source of demand just weeks before the main U.S. export season begins in September. Traders told Reuters that Chinese importers have already secured about 8 million metric tons of soybeans from South America for September delivery and a further 4 million tons for October—volumes that in previous years would have been dominated by U.S. origin. The early bookings suggest China could largely bypass U.S. cargoes during the prime September-January window, potentially costing American growers billions of dollars in revenue. Persistent trade tensions are keeping U.S. soybeans subject to a 23% Chinese tariff, undermining their competitiveness despite prices that are roughly $40 a ton cheaper than comparable Brazilian shipments for October. With Chicago futures near five-year lows and Brazil forecast to run short of beans only late in the season, analysts warn that U.S. exporters may struggle to regain market share unless the tariff barrier is eased.