Myriad Genetics’ share price performance over the past 12 months has been erratic to say the least, but the major disappointments in its second-quarter results, released after market yesterday, have pushed the stock to its lowest price since April 2017. Second-quarter revenues of $195m were not only 10% lower than a year earlier, but they were far below Myriad’s own guidance of around $211m. The group blamed billing changes to do with its prenatal testing business, which it gained via its $375m acquisition of Counsyl in 2018; revenues form this unit almost halved year-on-year. Its chief executive, Mark Capone, is to step down immediately, with finance chief R Bryan Riggsbee taking the helm in the interim. The new leadership will doubtless wish to stabilise the company’s stock. A 54% jump in the price late last July, when United Health said it would reimburse the group’s GeneSight multi-gene panel, was wiped out a week later by disastrous fourth-quarter financials. Indeed, every quarterly update by the company since November 2018 precipitated a crash, and investors will surely be tiring of this volatility.