CHICAGO, July 17 (Reuters) - Spot basis bids for corn delivered to U.S. Midwest elevators and processing plants were flat to lower on Thursday on generally slow demand, while soybean basis bids were mostly unchanged.

• An elevator in Cincinnati, Ohio, cut its spot corn basis bid by 7 cents a bushel and a river elevator in Seneca, Illinois, lowered its spot corn bid by a nickel. Basis bids at corn ethanol plants were flat to down 5 cents a bushel.

• In one exception to the corn market's weak tone, a processor in Cedar Rapids, Iowa, raised its spot basis bid by 5 cents a bushel for grain delivered in the second week of this month to draw out immediate supplies. Its bid for grain delivered in the third week was 6 cents below the spot bid.

• Chicago Board of Trade corn futures slumped on Thursday after U.S. corn export sales last week fell well short of market expectations. A possible shift by Coca-Cola away from high fructose corn syrup in its drinks stoked further demand concerns.

• CBOT September corn futures CU25 were down 4 cents at $4.01-1/4 a bushel at 1 p.m. CDT (1800 GMT), while new-crop December corn CZ25 was down 3-1/4 cents at $4.20-3/4 a bushel.

• CBOT August soybean futures SQ25 were up 7 cents at $10.20-1/2 per bushel. New-crop November soybeans SX25 were up 6 cents at $10.26-1/2 a bushel.

Basis values are quoted against CBOT futures in cts/bu:

NOTE: 0 = Option price, UNC = Unchanged, UNQ = Unquoted

NC = Not comparable, DP = Delayed price, N/A = Not available,

F = January, H = March, K = May, N = JulyQ = August, U = September, X = November, Z = December

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LINKS: 0#USCSHGRN-PM

For U.S. forward basis spreadsheets, please click:

CORN/BASIS, SOYA/BASIS, WHEAT/BASIS, MILO/BASIS

- CBOT corn report COR/

- CBOT soybean report SOY/C

- CBOT wheat report WHE/C

- U.S. grain barge freight values BG/US

- U.S. Midwest cash grain PM GRA/PM

- U.S. CIF/FOB Gulf Grain GRA/F

(Reporting by Karl Plume Editing by Sandra Maler)

((karl.plume@thomsonreuters.com; +1 313 484 5285))