Global Atomic (TSE:GLO) shareholders should be worried about its cash burn. For the purposes of this article, cash burn is the annual rate at which an unprofitable company spends cash to fund its growth; its negative free cash flow. This kind of short runway puts us on edge, as it indicates the company must reduce its cash burning significantly, or else raise cash imminently. In our view, global Atomic doesn't yet produce significant amounts of operating revenue.