July 25 (Reuters) -Spot basis bids for corn shipped by barge to U.S. Gulf Coast terminals firmed on Thursday, though traders noted that prices have fluctuated in recent days on spotty barge availability and as buyers hunted for supplies.

* CIF soybean bids for nearby loadings were mixed, with prices in the spot market seeing more volatility than seasonally normal, traders said.

* Exporters sold 264,000 metric tons of U.S. soybeans to unknown destinations for 2024/25 delivery, the U.S. Department of Agriculture said Thursday.

* The USDA separately reported U.S. soybean export sales for the week ended July 18 were 829,700 metric tons for the 2024-25 marketing year, compared to analysts' estimates for 500,000 to 900,000 tons. Weekly soybean sales of 88,600 tons for the 2023-24 marketing year fell below estimates for 100,000 to 400,000 tons.

* USDA also reported weekly U.S. corn export sales of 745,200 tons for the 2024-25 marketing year, exceeding analysts' estimates for 100,000 to 600,000 tons.

* CIF corn barges loaded in July were bid around 70 cents over Chicago Board of Trade September futures CU24, up 1 cent. Barges loaded in August were bid about 71 cents over futures, up 1 cent.

* FOB offers for corn shipments loaded from the Gulf in August were steady at around 78 cents over September futures.

* CIF soybean barges loaded in July were bid at 85 cents a bushel over CBOT August futures SQ24, up 6 cents from Wednesday - though the spread between bids and offers tightened, traders said. Bids for August barge loadings were 64 cents over futures, down 2 cents.

* FOB export premiums for soybean shipments loaded from the Gulf in August were steady at around 87 cents over CBOT August futures.

Reporting by P.J. Huffstutter

For displays of CIF basis, click on the codes in brackets: U.S. CIF Gulf soybeans GRYM U.S. CIF Gulf corn GRYN U.S. CIF Gulf SRW wheat GRYO U.S. CIF Gulf HRW wheat GRYP
For displays of FOB basis, please click on the following codes in brackets: U.S. FOB Gulf corn GRZC U.S. FOB Gulf soybeans GRZD U.S. FOB Gulf SRW wheat GRZE U.S. FOB Gulf HRW wheat GRZF LINKS Corn prices page: cpurl://apps.cp./cms/?pageid=corn-cash-market
Wheat prices page: cpurl://apps.cp./cms/?pageid=wheat-cash-market
U.S. barge freight BG/US
U.S. export sales estimates USDA/EST
U.S. grain export summary GRA/U
Brazil soybean export prices SYBS
Brazil corn export prices SYBX
Argentina grain prices GRA/ARG
Russia grain prices GRA/RU