McDonald's ( symbol) loyalists got a snack Thursday when the fast-food chain previewed third-quarter earnings that were slightly above Wall Street forecasts. But the company also saw same-store sales growth for September continue a recent deceleration that has emboldened company critics in the last few months.

Excluding a gain, McDonald's expects to earn 56 cents a share in the quarter, 2 cents ahead of the Thomson First Call consensus estimate. The company earned 59 cents a share in the year-ago quarter including a net 5-cent gain.

The outlook sent McDonald's shares up 45 cents, or 1.4%, to $32.12 after hours. The stock lost about 2% in the regular session.

McDonald's said U.S. same-store rose 2.7% in September. That's down from August's gain of 3.2%, July's gain of 4.9% and June's gains of 5.4%. Overall same-restaurant sales rose 3.9% in September, down from a gain of 7.3% in the year-ago month.

While McDonald's has now posted 30 straight months of same-store sales gains, the recent leveling off has stalled a two-year-old rally in the stock at about $34 a share. Last month, an activist hedge fund bought a stake in the restaurant chain and is expected to push for asset divestitures.

McDonald's announced a plan last month to sell part of its Chipotle chain in an IPO and return more cash to shareholders via a higher dividend and buyback. The stock has lost about 30 cents since the night before that announcement was made.