Or this is a bit slicker:

Sub Table_Insert()
    Dim tbl As ListObject
    Set tbl = ActiveSheet.ListObjects("Table1")
    With tbl
        .ListColumns.Add
        .HeaderRowRange(.Range.Columns.Count) = "Client Name"
        .HeaderRowRange(.Range.Columns.Count).Offset(1).Formula = "=TRIM(UPPER(SUBSTITUTE(R[0]C[-13],""."","""")))"
        .HeaderRowRange(.Range.Columns.Count).Columns.EntireColumn.AutoFit
    End With
End Sub