Something tells me your report design is unusual, and that may be the real problem. Usually data goes into (e.g.) textboxes, not labels.
You would have to decide at what character count you will do this, as there's no way (at least that I'm aware of) to do anything automatically. The possible problem with that is, unless you use a fixed width font x number of characters have different widths depending on the characters present. W's take up a lot more space than I's.
You would have to write code that gets the character count of your text and reduce the font size accordingly. Something like
Code:
Select Case Len(Me.lblNames)
Case Is > 50
Me.lblNames.FontSize = 8
Case 25 To 50
Me.lblNames.FontSize = 10
Case Else
Me.lblNames.FontSize = 12
End Select
Your report design might require such code to go somewhere other than the report load event.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.