Bank stocks have been on quite a run since Election Day, but further upside may now be limited.In a new report, Bernstein analyst Kevin Pierre downgraded four U.S. regional banks from Outperform to Market Perform. According to Pierre, the bank stocks are simply fully-valued at this point.“Even factoring in the potential for positive revisions and regulatory easing, we struggle to find compelling upside to any of the mid-cap bank stocks in our coverage,” Pierre explains.Bernstein’s four downgrades include Citizens Financial Group Inc , Fifth Third Bancorp , KeyCorp and Zions Bancorp .Pierre points out that bank stocks have rallied 15 percent since Trump’s election, but the president-elect has provided few details about potential policy actions that would benefit the banks. Pierre believes that potential positive impacts of looser regulations, lower taxes and higher interest rates are already priced into most bank stocks.In addition to the four downgrades, Bernstein maintains Market Perform ratings on Comerica Incorporated , Huntington Bancshares Incorporated , M&T Bank Corporation and Synovus Financial Corp. .Despite the downgrades, Bernstein upped its price targets for all eight of the U.S. regional banks under its coverage.Latest Ratings for CFG DateFirmActionFromToNov 2016PiperJaffrayDowngradesOverweightNeutralNov 2016BernsteinDowngradesOutperformMarket PerformNov 2016OppenheimerDowngradesOutperformMarket PerformView More Analyst Ratings for CFG View the Latest Analyst Ratings