Smithfield Foods Inc.'s stock declined to a 4.5 year low, as high corn prices and Midwest floods dampened investor confidence in the top US pork producer.

By the end of the week, the shares had stabilized, but analysts said the stock's value remains inversely proportional to corn prices, reports Wisconcin Ag Connection.

Smithfield's shares sank to US$23.13 at the end of trading last Wednesday on the New York Stock Exchange, down more than 27 percent from its US$31.78 close on May 29, less than a month before.

Corn prices hit record levels last week, exceeding US$7 a bushel.

The figure is up 20 percent in the past month and more than 80 percent over the past year.

Smithfield, the world's largest hog processor and producer, acknowledged the issue two weeks ago. The company reported that fourth-quarter income fell 94 percent, or nearly US$35 million , driven down by a US$129 million loss in hog production.