NEW YORK (AP) _ Some of the stocks that are moving substantially or trading heavily Thursday on the New York Stock Exchange, Nasdaq Stock Market, and American Stock Exchange.

NYSE

Waste Management, down 5 3/4 to 23 1/4

The Oak Brook, Ill.-based trash hauling company said late Wednesday that Chairman and Chief Executive Officer Ronald T. LeMay and Chief Financial Officer John D. Sanford had resigned, effective immediately.

Data General, down 4 3/8 to 19

The Westboro, Mass.-based company reported third-quarter earnings that fell below Wall Street analysts' estimates.

Sun Healthcare Group, up 5/8 to 19 5/8

The Albuquerque, N.M.-based company reported third-quarter earnings that topped Wall Street analysts' estimates.

Aames Financial, up 1 1/4 to 14 3/8

The Los Angeles-based home equity lender reported first-quarter earnings that topped Wall Street analysts' estimates.

NASDAQ

Phycor, down 5 9/16 to 24

MedPartners, down 1 1/8 to 25 3/4 on the NYSE

Birmingham, Ala.-based MedPartners, the largest company in the physican-management business, is being acquired by the No. 2 company, PhyCor of Nashville, Tenn., in a deal worth about $7 billion.

Apache Medical Systems, down 5/8 to 2 3/8

The McLean, Va.-based company reported a third-quarter loss that fell below Wall Street analysts' estimates.

Pegasystems, down 9 3/8 to 18 3/8

The Cambridge, Mass.-based company said an ``unanticipated issue'' raised by its auditors has forced the company to reschedule the release of its third-quarter results, and may possibly lead the company to restate its second quarter results.

Quaker Fabric, down 3 3/4 to 19

The Fall River, Mass.-based maker of woven upholstery fabrics for furniture reported third-quarter earnings that fell below Wall Street analysts' estimates.

Einstein/Noah Bagel, down 1 5/16 to 8 15/16

The Golden, Colo.-based company was downgraded by a number of investment firms, including BT Alex, Brown and Piper Jaffray.