Short interest in Spero Therapeutics Inc (NASDAQ:SPRO) increased during the last reporting period, rising from 1.18M to 1.65M. This put 3.43% of the company's publicly available shares short.

Based on the recent average volume of 630.47K shares traded per day, it would take 2.61 day(s) for holders of this short interest to close out their positions without sending the stock sharply higher.