A sharp up­turn in the val­ue of the dol­lar sent prices for oil, gold and oth­er com­modi­ties sharply low­er. Grain prices fell, but beans rose. Wheat lost 23.25 cents to $6.5675 a bushel and corn lost 16 cents to US$5.625 a bushel. Soy­beans edged up 4.75 cents to US$13.8675 a bushel.

The dol­lar's spike against the eu­ro came at mid­morn­ing Tues­day af­ter Egan Jones, a small cred­it rat­ings agency, cut its rat­ing on Span­ish gov­ern­ment debt. Even though the agency isn't as well-known as Moody's or Stan­dard & Poor's, the re­port was enough to rekin­dle wor­ries that Spain's fi­nan­cial trou­bles could deep­en.

The eu­ro slid to a 22-month low against the dol­lar. When the dol­lar ris­es in val­ue, it in­stant­ly re­duces de­mand for com­modi­ties like oil and gold be­cause they be­come more ex­pen­sive for in­vestors who use oth­er cur­ren­cies such as eu­ros. Un­like glob­al mar­kets for stocks, bonds and oth­er fi­nan­cial se­cu­ri­ties, which trade in a va­ri­ety of cur­ren­cies, most com­modi­ties are priced on­ly in dol­lars even though they're pro­duced and con­sumed in coun­tries around the world. That makes their prices high­ly sen­si­tive to changes in the val­ue of the dol­lar.