St. Louis-based Post Holdings (NYSE:POST), owner of the Post brand, and maker of such familiar boxed cereals as Shredded Wheat, Grape Nuts, and Honeycomb, announced Thursday that, in order to improve efficiency of operations, and "to better position the Company for future growth," it may have to close its manufacturing facility in Modesto, California.

Closure would necessarily affect the 140 employees at the plant. Post will consult with union representatives at the plant before making a final decision. The company expects to know which way it will go by the end of April.

"Excess capacity" is the problem, explained Post President and Chief Operating Officer Terence E. Block. "This initiative, if we proceed, would provide the increased efficiency necessary to compete in today's environment," he said.

Post shares reacted negatively to the news, falling 0.4% in Thursday trading to close at $42.01.