Shares of the Financial Select Sector SPDR Fund were trading lower Friday afternoon, which has investors worrying about the outlook for the banking sector.The Current Case Against BanksFBR Capital Markets' Paul Miller was a guest on CNBC's "Squawk On The Street" segment on Friday to discuss the mixed results seen in the banking sector so far.The banking analyst suggested that there is little opportunity for bank stocks to rise unless investors get clear signs that the U.S. 10-year Treasury will rise.However, once the 10-year does rise, Miller said that investors will "sit there and say — I'm going to be buying these things all day long."Some of the stocks investors should be buying include banks with exposure to mortgages, such as Wells Fargo & Co , U.S. Bancorp and PNC Financial Services Group Inc . These companies will likely benefit the most from another home refinancing boom — but there are some risks in this trade.The analyst cautioned that if rates stay unchanged, then the refinancing boom will "burn itself out," and investors who bought these names will be "sitting with these things probably where they're trading today."