Oct 18 (Reuters) -Basis bids for corn shipped barge to the U.S. Gulf Coast and loaded for export firmed on Friday on good demand and lower futures prices, while soybean basis bids pulled back slightly after surging earlier in the week, traders said.

* A steady stream of corn export sales this week, mostly to Mexico, firmly supported prices.

* The U.S. Department of Agriculture (USDA) on Friday confirmed 125,000 metric tons of U.S. corn sales to undisclosed buyers. It was the third straight day with a daily USDA announcement, with sales totaling more than 2 million tons in that time.

* CIF corn barges loaded in October were bid 2 cents higher at 90 cents over Chicago Board of Trade (CBOT) December CZ24 futures. The spot bid rose 20 cents this week.

* FOB Gulf offers for November and December corn shipments held at about 115 cents over futures.

* Exporters have been bidding aggressively for spot shipments of high quality soybeans from the Midwest to blend with damaged Delta soybeans, sending nearby prices soaring this week.

* CIF October soybean barges were bid 111 cents over CBOT November SX24 soybean futures, down a penny from Thursday but up 20 cents from a week ago. Barges that were loaded in the first half of this month were bid around 115 cents over futures on Friday.

* FOB offers for November soybean shipments held firm at 135 cents over futures.

Reporting by Karl Plume; editing by Diane Craft

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