Check out the companies making headlines after the bell: Pinterest — Shares of the image-sharing company popped more than 19% despite a miss on the top and bottom lines as activist investor Elliott Management revealed it is now the largest investor. The company also beat monthly active user estimates.Simon Property Group — Simon Property’s stock rose more than 1% in extended training despite a revenue miss. The REIT beat earnings estimates by 8 cents and shared earnings guidance for the full year that topped expectations.Arista Networks — The cloud computing stock added 4.6% after hours following a beat on the top and bottom lines in the latest quarter. Arista Networks reported adjusted earnings of $1.08 per share on revenues of $1.05 billion and posted strong revenue guidance for the current quarter.Avis Budget — The rental vehicle company gained 6% in extended trading on the back of a better-than-expected quarter. Avis Budget posted adjusted earnings per share of $15.94 per share on $3.24 billion in revenue. Analysts anticipated earnings of $11.48 a share on revenue of $3.17 billion.ZoomInfo — Shares of ZoomInfo jumped 12% postmarket after topping earnings and revenue estimates for the most recent quarter. The company reported adjusted earnings of 21 cents per share on $267 million in revenue and lifted its guidance for the full year.