The volatility comes from changing beliefs about the importance of factors other than day-to-day business in projecting future earnings. Lately, the stock has dropped because of a large risk that Medicare will substantially cut reimbursement for BRACAnalysis, the company's predominant product.
Myriad's prospects depend to a remarkable degree on maintaining (or not) the perception that its trademarked tests are better than other providers' near-equivalents. That is a difficult and uncertain enterprise, and frankly, more familiar in the prepared food industry than in medical testing.
High percentage of shorts greatly contributes to the volatility.
People are worried that MYGN might be losing market share as parts of some of their patents have not held up in court. However, most claims have and MYGN is suing several companies for patent infringement. Those companies have filed countersuits.
Theres also concern that the approved payment for certain tests will be reduced and cut into profits.