(Adds company comments, details, updates share price)
By Nandita Bose and Yashaswini Swamynathan
Feb 25 (Reuters) - Dollar Tree Inc posted better-than-expected quarterly sales on Wednesday and said it expected to reach an agreement with the U.S. antitrust regulator by early March on store divestitures to get approval for its acquisition of larger rival Family Dollar Stores Inc.
Dollar Tree said it remained confident it would not have to divest more than 300 stores to get the approval, which was earlier expected by the end of March.
The discount retailer had said earlier this month that the U.S. Federal Trade Commission was reviewing about 500 stores for divestiture and might identify more stores for review.
Dollar Tree, which will replace Dollar General Corp as the No. 1 U.S. discount retailer if it acquires Family Dollar, said same-store sales rose 5.5 percent, including the impact of currency movements, in the fourth quarter ended Jan. 31.
"Both companies are ready to integrate and the lengthy delays for this process have afforded us a significant time to focus on integration planning," Chief Executive Bob Sasser said on an earnings conference call.
Sasser said the company has identified the opportunity to realize at least $300 million in annual cost synergies by the end of 2020. The company will selectively re-banner Family Dollar stores to the Dollar Tree brand going forward, he added.
Dollar Tree's quarterly sales rose about 11 percent, helped by higher demand for party supplies, household products and food during the holiday season.
Family Dollar meanwhile estimated a 4.1 percent rise in net sales in the two months ended Jan. 31.
Shares of Dollar Tree, which sells items for $1 or less at its namesake chain, rose 2.8 percent to $79.64.
Dollar Tree forecast adjusted earnings of between 69 cents and 74 cents per share and revenue of $2.15 billion to $2.20 billion for the first quarter. Analysts on average were expecting a profit of 76 cents per share and revenue of $2.21 billion, according to Thomson Reuters I/B/E/S.
Dollar Tree's net income fell 3 percent to $206.6 million, or $1.00 per share, in the fourth quarter. Excluding items, the company earned $1.16 per share.
Revenue rose to $2.48 billion from $2.23 billion. Analysts on average had expected a profit of $1.15 per share and revenue of $2.47 billion. (Reporting by Nandita Bose in Chicago and Yashaswini Swamynathan in Bengaluru; Editing by Kirti Pandey and Meredith Mazzilli)