Yum! Brands calls active amid speculation of an activist investor stake Yum! Brands January 72 and 72.5 calls are active on total call volume of 7,600 contracts (900 puts) amid speculation of an activist investor stake. January call option implied volatility is at 32, February is at 31, April is at 22; compared to its 26-week average of 22 according to Track Data. Active call volume suggests traders taking positions for large price movement.