Cash flow matters in the financial world. So while not a core CAN SLIM variable, cash flow per share is worth a close look. IBD Chairman and founder William O’Neil has noted that many fast-growing companies show full-year operating cash flow per share that’s at least 20% greater than actual earnings per share. So if a company has annual earnings of $2 a share, look for cash flow from operations of at least $2.40 a share.