NightHawk, Sonic: Late Day Volume Movers

NEW YORK (TheStreet) -- Several small-cap stocks were moving on above-average volume during Friday's session.

Purple Communications (PRPL Quote) plummeted by 80 cents, or nearly 50%, to 81 cents after the company late Thursday said it will voluntarily delist from the Nasdaq as part of its strategy to conserve resources and manage costs and administrative burden. Volume topped 306,000 shares, compared to the 50-day average daily volume of 12,000, according to the Nasdaq.

NightHawk Radiology Holdings (NHWK Quote) dropped by $1.58, or 23.4%, to $5.18 after the company late Thursday offered weak guidance for the fourth quarter, saying it expects earnings of 8 cents to 10 cents a share on revenue of $38 million to $40 million, compared to the Thomson Reuters average estimate for earnings of 15 cents a share on revenue of $40.13 million. Volume topped 3 million shares, compared to the 50-day average daily volume of 174,000, according to the Nasdaq. ...