Doubts that Greece will reach a deal with its creditors sank the markets with the Dow plummeting 178 points to 17,966. Nasdaq dropped 37 points to 5,122.

On the upside

Turtle Beach (Nasdaq: HEAR) partnered with AuDConnex to distribute its HyperSound Clear hearing healthcare solution.

Flotek Industries (NYSE: FTK) chief executive John Chisholm will present at the Global Hunter Securities GHS 100 Energy Conference next Wednesday.

Topeka Capital Markets upgraded Merge Healthcare (Nasdaq: MRGE) from a Hold rating to a Buy rating.
 
On the downside

Investors locked in profits on DS Healthcare Group (Nasdaq: DSKX).

Progenics Pharmaceuticals (Nasdaq: PGNX) chief executive Mark R. Baker will present at the Cantor Fitzgerald’s Inaugural Healthcare Conference on July 8, 2015 but the stock price fell.

Shares of Willbros Group (NYSE: WG) continued falling.
 
In the broad market, declining issues outpaced advancers by a margin of nearly 5 to 2 on the NYSE and by more than 5 to 2 on Nasdaq. The broader S&P 500 tumbled 15 points to 2108. Bitcoin slipped $2 to $242.