CALX - Why Calix Stock Popped Today December, 29 2021 05:28 PM Calix Inc Shares of Calix (NYSE: CALX) jumped today on news that it would be added to the S&P MidCap 400 index. The stock closed up 14.5% as a result. Image source: Getty Images. Continue reading For further details see: Why Calix Stock Popped Today