Option Explicit

Sub Unbekannt()
    Dim LoZeile As Long
    Dim LoSpalte As Long
    Dim LoI As Long
    LoZeile = ActiveSheet.UsedRange.SpecialCells(xlCellTypeLastCell).Row
    LoSpalte = ActiveSheet.UsedRange.SpecialCells(xlCellTypeLastCell).Column
    For LoI = LoSpalte To 1 Step -1
        Columns(LoI).Insert Shift:=xlToRight
        Range(Cells(1, LoI), Cells(LoZeile, LoI)) = "&"
    Next LoI
End Sub