GRAINS-Wheat slips further on global supply pressure, Ukraine ceasefire talks

CANBERRA/PARIS, Dec 16 (Reuters) - Chicago wheat futures extended losses on Tuesday, hovering near their lowest level since late October, as bumper harvests in Argentina and Australia and rising expectations of a ceasefire in Ukraine reinforced supply pressure.

Corn futures also eased, weighed down by competition from wheat for livestock feed demand.

Soybeans steadied after hitting seven-week lows on Monday due to concerns about U.S. export demand and expectations for a bumper harvest in Brazil.

The most-active wheat contract on the Chicago Board of Trade (CBOT) Wv1 was down 0.6% at $5.17-1/2 a bushel at 1110 GMT, after touching its lowest since October 24 at $5.15-3/4.

"Global wheat prices remain under pressure due to Southern Hemisphere harvests and rising production estimates," said Commonwealth Bank analyst Dennis Voznesenski.

The Rosario Grains Exchange last week raised its production estimate for Argentina to 27.7 million metric tons from 24.5 million tons, while Australia is on track for its third-biggest harvest.

Their crops round out a year of large harvests across major producing nations, and there is no sign yet of major production setbacks in 2026.

"Sentiment was further weighed (down) by rising hopes of an end to Russia's war in Ukraine," commodity data firm CM Navigator said of wheat.

The United States has offered to provide NATO-style security guarantees for Kyiv as U.S. and European negotiators reported progress in talks on Monday, though a deal on territorial concessions remained elusive.

An end to the conflict could facilitate grain exports for the two major producing countries.

CBOT corn Cv1 eased 0.3% to $4.38-1/2 a bushel after falling to a three-week low on Monday. CBOT soybeans Sv1 inched up 0.1% to $10.73 a bushel.

Traders have been disappointed at the pace of Chinese purchases of U.S. soybeans since an end-October trade truce between Washington and Beijing.

U.S. domestic crushing of soybeans slowed more than expected in November but was still a record high for the month, according to the National Oilseed Processors Association (NOPA).