The top after-market NASDAQ stock market movers on Oct.28 include Momenta Pharmaceuticals, HMS Holdings, Clayton Williams Energy, MedAssets, Fuel Systems Solutions and Netgear.

Gainers

Shares of Momenta Pharmaceuticals, Inc. (NASDAQ: MNTA) climbed about 20 percent, or $2.36, to $14.60 after it won a court ruling that will temporarily block rivals from selling a generic version of its anti-clotting drug, Lovenox.

HMS Holdings Corp. (NASDAQ: HMSY) stock gained about 15 percent, or $3.53, to $27.13 after it reported better-than-expected third quarter earnings on 15 percent growth in revenues. For the third quarter, the company earned 17 cents a share, up from analysts' consensus expectation of 16 cents.

Shares of Clayton Williams Energy, Inc. (NASDAQ: CWEI) rose 9.7 percent, or $6.80, to $77.01 after it reported strong third-quarter results. Net income attributable to stockholders was $74.5 million, or $6.13 per share, compared to $11.6 million, or 96 cents per share, last year.

Losers

Shares of MedAssets, Inc. (NASDAQ: MDAS) plunged 12 percent, or $1.35, to $9.85. The stock closed regular trading session 13 percent higher at $11.20.

Shares of Fuel Systems Solutions, Inc. (NASDAQ: FSYS) were down about 7 percent, or $1.63, to $22.24. They ended Friday's regular trading session up 1.14 percent to $23.87.

Shares of Netgear, Inc. (NASDAQ: NTGR) slipped 6.45 percent, or $2.28, to $33.08. The stock closed Friday's regular trading session up 7 percent to $35.36.