China is clearing the way for more purchases of American soybeans in an apparent boon for U.S. farmers. There’s just one thing getting in the way—cheap Brazilian supplies.

As Beijing and Washington edge closer to an initial trade resolution, the Asian nation is said to have granted tariff waivers on 10 million metric tons of U.S. soy. But market reaction to the news has been tepid, with futures in Chicago little changed. Part of traders’ indifference is explained by lower prices in Brazil.

The South American nation won the lion’s share of soybean shipments to China during the more than year-long trade war. But with the U.S. and China returning to the negotiating table, Brazilian soybean export premiums have plunged 44% since mid-August.

Now, with prices from each shipper near parity, China can pick and choose. A weaker Brazilian currency has helped tip the scales recently to South America at the expense of farmers in North America who have harvested about half of this year’s crop.

For shipments starting in January, when the harvest in the South American nation begins, Brazil is more competitive than the U.S., according to Pedro Dejneka, a partner at Chicago-based MD Commodities. That advantage is even more evident in February to April.

“The fact of China buying from South America over the last 10-15 days tells the market that buyers will rely on what will be better for their bottom line,” Terry Reilly, senior commodity analyst at Futures International LLC, said in an email.