Here are today's top Wall Street analyst ratings where finbox.io's unbiased fair value estimates supported the recommendation.Top Upgrades KeyCorp initiated coverage on Cooper Tire & Rubber Co. (CTB) at overweight. Shares currently have over 30% upside.Credit Suisse reiterated its buy rating on Parexel International (PRXL). Stock's trading at a 25% discount to fair value.RBC Capital raised its target price for Discovery Communications (DISCA) to $33-$35 per share. Finbox.io data concurs.BMO Capital upgraded Pan American Silver Corp. (PAAS) to outperform. The company is +15% undervalued.Top Downgrades Barclays downgraded Level 3 Communications (LVLT). Shares are currently trading at are large premium.Bank of America downgraded Vulcan Materials (VMC). Ten valuation models show the stock is 30% overvalued.Macquarie downgraded ViaSat (VSAT) to underperform. Fundamentals support rating change.Bank of America downgraded Summit Materials (SUM). Shares currently have little margin of safety.