A pedestrian crosses the street in front of a Rite Aid store in Los Angeles.

Rite Aid is chopping its annual profit forecast three days before its shareholders vote on whether to approve the sale of the company.

Shares plunged 12 percent Monday at the opening bell.

Rite Aid said that generic drug pricing isn't what it expected in April when it first made its forecast for fiscal 2019. It reaffirmed that forecast as recently as June.

The company now expects a range of break-even to an adjusted loss of four cents per share. It had predicted earnings of two cents, to six cents per share.

FactSet says analysts had expected per-share earnings of 2 cents.

Albertsons announced plans to buy Rite Aid's stores in February. Two shareholder advisory firms and a big investor have come out against the deal. Shareholders will vote Thursday.