Discount retailer Dollar Tree raised its sales outlook for the year after recording its strongest growth in quarterly same-store sales since 2011.
Shares of the company, which has agreed to buy Family Dollar Stores for $8.5 billion, rose 3 percent premarket.
Dollar General countered with a $9.1 billion bid that has been rejected by Family Dollar over antitrust concerns.
Dollar Tree, which like other discounters is facing competition from small-format stores opened by big retailers such as Wal-Mart Stores Inc, will become the largest dollar store chain if it pulls off its deal with Family Dollar.
Dollar Tree's same-store sales rose 5.9 percent in the third quarter ended Nov. 1, beating the average analyst estimate of 4 percent, according to research firm Consensus Metrix.
The company said on Thursday it expected sales of $8.52 billion-$8.58 billion for the year ending January, up from its previous forecast of $8.44-$8.55 billion.
Dollar Tree, which also operates Deal$ and Dollar Bills stores, tightened its earnings forecast range to $2.97-$3.04 per share from $2.94-$3.06.
Net income rose 6 percent to $133 million, or 64 cents per share. Excluding items, the company earned 69 cents per share.
Net sales rose 11 percent to $2.1 billion.
Analysts on average had expected earnings of 64 cents per share on revenue of $2.06 billion, according to Thomson Reuters I/B/E/S.
Dollar Tree's shares were trading at $64.50 premarket. Up to Wednesday's close, they had risen 15.5 percent since July, when the company made its bid for Family Dollar.