Option Explicit
Sub Test()
Dim i As Integer
Dim Val As Variant
Range("D2:D65536").ClearContents
For i = 1 To 3
Val = Range(Cells(2, 1), Cells(Rows.Count, 1).End(xlUp)).Value
Range("D" & Rows.Count).End(xlUp)(2).Resize(UBound(Val)).Value = Val
Next
End Sub