Select
    [PORT_DATE],
    Count (*) as [Loan Count],  --this works fine
    sum(Case when [Closed or Fallen Out] ='c' then 1 else 0 end) as [Actual Closed Loans],--this works fine
    sum(Case when [Closed or Fallen Out] ='C' then 1 else 0 end)/count(*) as [Actual Closing Ratio], --although code works doesnt produce correct result, output for this variable is all zeros
From dbo.XYZ
Group by [PORT_DATE]
order by [PORT_DATE]