Large speculators cut back on their bearish exposure to U.S. grain futures as an unexpected holiday season rally forced traders to cover short positions.

Futures market trading is typically quiet during December as traders try to protect profits they made during the year.

But concerns that damage to the Australian wheat crop would boost overseas demand for U.S. supplies sent wheat prices up 14.3 percent during the week ended December 7, forcing noncommercial traders to cut their net short in Chicago Board of Trade wheat by 30,339 contracts.

The large speculators held a net short position of 15,707 contracts as of Dec. 7 after cutting 10,475 short contracts and adding 19,864 longs, according to the Commodity Futures Trading Commission’s commitments of traders report issued on Friday.