Insider Buying Activity Rises at Tandem Diabetes Care Amid Volatile Trading Tandem Diabetes Care’s stock climbed over 6% on Thursday, closing at $17.67, as insider Jean-Claude Kyrillos, COO, recently purchased 10,538 shares. Despite the uptick, the stock remains near its 52-week low and has seen a 46% drop over the past year, highlighting ongoing investor caution.123