Costco Wholesale Corp. said late Tuesday its board of directors has declared a special dividend of $7 a share and authorized an increase of 5 cents in the company's quarterly dividend. "Our strong balance sheet and favorable access to the credit markets allow us to provide shareholders with this dividend, while preserving financial and operational flexibility to continue to grow our business globally," Chief Financial Officer Richard Galanti said in a statement. The special dividend is payable on May 26 to shareholders of record on May 10. The aggregate payment will be about $3.1 billion, to be funded primarily through additional borrowing, Costco said. The company's regular quarterly cash dividend of 50 cents per share will also be payable on May 26 to shareholders of record on May 12. Costco shares rose 3.8% after ending the regular trading session up 0.2%.