Rewrites throughout, adds USDA acreage and stocks data, adds quote, updates prices, adds byline, changes dateline from PARIS/BEIJING

By Karl Plume

CHICAGO, June 30 (Reuters) - U.S. corn futures jumped on Tuesday after the U.S. Department of Agriculture said American farmers planted 3% fewer acres of the crop this year and that stocks of the grain have tightened by more than traders had expected.

Wheat futures rallied after the government estimated plantings well below expectations, while soybean futures followed corn prices higher as the USDA pegged planted acres in line with trade estimates.

U.S. farmers planted 95.343 million acres of corn in 2026, down from 98.788 million last year but above the average analyst estimate for 94.992 million, the U.S. Department of Agriculture said in its annual acreage report. Growers scrambled to capitalize on rising grain prices and favourable growing weather, analysts said.

Corn stocks as of June 1 were estimated at 5.295 billion bushels, below the average estimate of 5.408 billion.

"The higher (corn) acreage was equalled out by lower stocks," said Craig Turner, consultant at StoneX. "For corn the stocks being off is showing demand is out there for corn, and we'll probably continue to see that."

The USDA pegged soybean plantings at 85.365 million acres, up from 81.215 million in 2025 and on par with estimates. All wheat plantings were well below expectations at 42.740 million acres, compared with the average pre-report estimate for 43.858 million.

A favourable start to the U.S. Midwest growing season, strength in the dollar and falling oil prices following de-escalation in the Iran war have weighed on corn and soybean prices. Most corn contracts on the Chicago Board of Trade hit contract lows ahead of the USDA report.

CBOT December corn futures CZ26 were up 6-1/4 cents at $4.36-1/4 a bushel by 12:40 p.m. CDT (1740 GMT), rebounding from a contract low of $4.25-3/4 a bushel. New-crop November soybeans SX26 were up 6-1/4 cents at $11.45-1/4 a bushel.

CBOT September wheat WU26 gained 12 cents to $5.91-3/4 a bushel, after hitting a four-month low earlier in the session.