Plasma derived medicines sit in a strange corner of healthcare. Demand for immunoglobulins and related therapies keeps rising as more patients are diagnosed with rare immune disorders and chronic diseases, and only a handful of global groups control the complex chain from donation centers to finished drugs. At the same time this is a capital heavy business that relies on expensive collection sites, regulated manufacturing and tight quality controls, so missteps in operations or accounting can quickly show up in leverage and investor trust.

One of the sector’s leaders now finds itself exactly between these forces. It combines solid revenue growth, a double digit operating margin and roughly a one fifth share of the global immunoglobulin market with higher debt and lingering reputation damage after a short seller attack questioned its numbers. The stock trades for less than one times annual sales and at a single digit multiple of operating profit, which makes it look like a value story…