FILE PHOTO: An advertising sign is pictured at a Dollar Tree store in Pasadena, California August 31, 2015. REUTERS/Mario Anzuoni/File Photo

(Reuters) - Discount store operator Dollar Tree Inc DLTR.O reported quarterly same-store sales on Thursday that fell short of estimates due to weak sales at its Family Dollar stores, sending its shares down 5 percent.

Overall sales at established stores open for more than a year rose 1.80 percent, while analysts had estimated a 1.84 percent increase, according to Thomson Reuters I/B/E/S.

The company’s net income rose to $273.9 million, or $1.15 per share, in the second quarter ended Aug. 4, from $233.8 million, or 99 cents per share, a year earlier.

The company said net sales rose to $5.53 billion from $5.28 billion.