Updated from August 25

Starbucks'

(SBUX) - Get Report

shares fell early Thursday after sales data released late Wednesday showed the company's red-hot sales growth cooled to a mere single-digit gain in August.

In its four-week period that ended on Sunday, the company posted $418 million in sales, up 25% from same period last year.

On a same-store basis, which compares results at shops open 13 months or more, Starbucks saw sales rise 8% year-over-year, the smallest gain in more than a year.

"We are very pleased with our strong monthly results," said Chairman Howard Schultz after the data's release late Wednesday. "These results reflect the continuing strength of our core business."

In February, Schultz warned investors that the company expected its overall sales to grow by only 20% on an annual basis in the future. Investors also should expect that Starbucks' same-store sales growth will range from about 3% to 7%, he added at the time.

But the company's sales have far exceeded those expectations in recent months. In the year to date, Starbucks revenue has grown 28% to $4.7 billion over the same period last year. Meanwhile, the company's comparable-store sales have grown 11% this year.

Starbucks shares fell $1.62, or 3.5%, to $44.42 in premarket trading Thursday.