Sub HideNotBold()

Dim ColK As Range
'find last row of data in column k plus 1
Dim lngLastRowk As Long
lngLastRowk = Range("k65536").End(xlUp).Rows
Set ColK = Range("k1:k" & lngLastRowk + 1)

'check each cell value
For Each c In ColK
If c.Font.Bold = True Then
c.EntireRow.Hidden = True
End If
Next c
End Sub