From Publishers Weekly:
Simon & Schuster and Barnes & Noble are locked in a dispute over terms. Although the exact nature of the disagreement is not yet clear, B&N has significantly reduced its orders from S&S. The main reason for the cutback seems to be, according to sources, B&N’s perceived lack of support from S&S.
. . . .
Unlike the disputes Amazon had with Macmillan and Independent Publishers Group, where the e-tailer pulled the buy buttons from titles released by those companies, B&N is continuing to carry S&S books, though quantities have been reduced.
Link to the rest at Publishers Weekly