Sub concat()
For i = 2 To ActiveSheet.Range("A" & Rows.Count).End(xlUp).Row + 1
derlignec = ActiveSheet.Range("D" & Rows.Count).End(xlUp).Row + 1
Cells(derlignec, 4).Value = Cells(i, 1).Value
Next i
For i = 2 To ActiveSheet.Range("B" & Rows.Count).End(xlUp).Row + 1
derlignec = ActiveSheet.Range("D" & Rows.Count).End(xlUp).Row + 1
Cells(derlignec, 4).Value = Cells(i, 2).Value
Next i
For i = 2 To ActiveSheet.Range("C" & Rows.Count).End(xlUp).Row + 1
derlignec = ActiveSheet.Range("D" & Rows.Count).End(xlUp).Row + 1
Cells(derlignec, 4).Value = Cells(i, 3).Value
Next i
End Sub