One of Greensboro’s biggest economic development successes in recent years is now a big bust. ProKidney is a publicly traded company and soon after the company agreed to locate a giant biomedical operation in Greensboro in 2023, the stock began falling like a rock from levels near $13 a share until it was, at some times, flirting with becoming a penny stock, which is a stock that falls to under a dollar a share.