Medstone International said it had “no idea”...

Medstone International said it had “no idea” why its stock has lost 28% of its value in recent trading. Medstone, which makes a device that shatters kidney stones with shock waves, went public through a June stock offering at $13 a share. The stock soared to $42 a share before plunging as low as $26 last Friday. The stock closed Monday at $30 in over-the-counter trading.