* Corn futures slump on massive U.S. corn crop

* Soybean futures follow, pressured by beefy global stocks

* Wheat futures extend losses after WASDE report

(Updates throughout, adds new headline, new bullets, updated market prices, new analyst comment, new byline and dateline)

CHICAGO, Nov 9 (Reuters) - The Chicago Board of Trade's most-active corn futures plunged sharply on Thursday after the government reported that U.S. farmers will produce the biggest-ever corn crop this year.

The report's forecast topped trade estimates. CBOT most-active corn contract dipped to $4.66-1/2, the lowest since Dec. 30, 2020, before inching back up.

Meanwhile, soybean futures slumped after the World Agricultural Supply and Demand Estimates report forecast that the global soybean stocks by the end of this season will be the largest on record.

Brazil’s crop agency, Conab, also raised its forecast of the country's 2023/24 soybean crop to 162.420 million metric tons, from 162.003 million previously, despite stressful hot and dry weather in key areas.

And soybean futures faced pressure as traders booked profits a day after the benchmark January contract hit its highest in nearly two months.

The sell-off came despite confirmation from the U.S. Department of Agriculture (USDA) that exporters sold 1.7 million metric tons of U.S. soybeans in the last day, including more than 1 million metric tons to China, extending a wave of recent export deals.

The confirmation came after Reuters reported on Wednesday that China had bought at least 300,000 metric tons of soybeans.

"And I'd think they (USDA) would have had that information in hand when they went into lock-up this morning," Rich Nelson, chief strategist for Allendale Inc.

Wheat futures extended losses on a strengthening U.S. dollar and the USDA's World Agricultural Supply and Demand Estimates (WASDE) for larger global supplies, decreased domestic use and higher ending stocks.

The most-active CBOT soybean contract was down 1.61% to $13.43-3/4 a bushel, as of 1804 GMT, while corn was down 1.79% at $4.67-1/2 a bushel. Wheat was down 2.07% at $5.80 a bushel. (Reporting by Brendan O'Brien in Chicago. Additional reporting by Julie Ingwersen, P.J. Huffstutter and Karl Plume in Chicago. Editing by Marguerita Choy)