William Blair analyst Margaret Kaczor said Inogen's results this quarter are disappointing after what seemed like a solid third quarter, although she notes that management suggested that excluding a manufacturing issue, business-to-business domestic sales would have come in roughly in line with the consensus, which suggests that underlying market dynamics appear stable. On the direct-to-consumer side, the miss was a surprise, although management "provided us with some confidence that underlying metrics remain encouraging for re-acceleration in 2020," Kaczor tells investors. She maintains an Outperform rating on Inogen shares.