Ruby Tuesday, Inc.'s (NYSE: RT) same-store sales unexpectedly fell 1 percent in the second quarter compared with a year earlier.

In Tuesday's extended session, the restaurant chain's shares traded recently at $7.79, off 3.9 percent.

Ruby Tuesday in October had predicted same-store growth of between 1 percent and 2 percent for the period ended December 2

Chief executive James J. Buettgen said guest counts in the recent period were "in line" with an industry benchmark but same-store sales were lower than expected.

Same-store guest count fell 1.3 percent from a year earlier.

Ruby Tuesday expects to post full results for its second period January 8.