Oppenheimer upgrades Wal-Mart (WMT

) to buy from neutral.

Analyst Bernard Sosnick says proposed plans at a shareholders' meeting last month to improve merchandising and operating methods seem to have paid off, with company forecasting stronger June comparable sales than had expected.

He says the June sales gain is due to pent-up demand for seasonal goods, developed during a cool spring. He notes the sales surprise appears to have set a floor under Wal-Mart shares and provided the basis for a trading rally.

Sosnick thinks the rally may extend over the next several months as it faces easy sales and corrects its merchandising and operating methods. He sees $2.65 fiscal 2006 (ending January) earnings per share and $3.11 fiscal 2007 earnings per share.