SpectraLink's ( SLNK) shares were surging after the company was upgraded by JPMorgan to overweight from neutral. Shares were rising 13.4% to $9.31 on heavy volume.

A.P. Pharma ( APPA) was higher on word it was granted an exclusive license to RHEI Pharmaceuticals to develop and sell APF530 in China and Taiwan. APF530 is currently in phase III trials in the U.S. for the prevention of acute and delayed chemotherapy-induced nausea and vomiting. Shares of A.P. Pharma were up 15% to $1.23.

Magnetek ( MAG) got a lift from an upgrade by B. Riley & Co., which raised its rating on the company to buy from neutral. Magnetek was recently gaining 10.7% to $3.83.

Streicher Mobile Fueling ( FUEL), a provider of petroleum-distribution services, slumped following its estimate that it will post a loss of $4.8 million for the year ended June 30. Last year, the company lost $1.46 million. Streicher also said it expects to report its fourth-quarter and year-end results to the Securities and Exchange Commission within the next 14 days. The stock was lower by 17.1% to $1.79.

Alphatec Holdings ( ATEC) skidded 16.4% after First Albany downgraded the stock. The firm took its rating to neutral from buy, and Alphatec was dropping 94 cents to $4.78.

More from Investing

Inside Carnival's Mind Blowing New Horizon Cruise Ship (Video)

Inside Carnival's Mind Blowing New Horizon Cruise Ship (Video)

Neel Kashkari: The Heart of Our Financial System Is More Radioactive Than Ever

Neel Kashkari: The Heart of Our Financial System Is More Radioactive Than Ever

McDonald's Criticized for Not Doing More in Wake of Sexual Harassment Claims

McDonald's Criticized for Not Doing More in Wake of Sexual Harassment Claims

Finding Stocks Right for You: Cramer's 'Mad Money' Recap (Friday 8/25/18)

Finding Stocks Right for You: Cramer's 'Mad Money' Recap (Friday 8/25/18)

Jim Cramer: The 10-Year Yield Could Go to 2.75%

Jim Cramer: The 10-Year Yield Could Go to 2.75%