Questions about Rule 144A and Regulation S DRs.

Hi guys,

I was confused by Rule 144A and Regulation S DRs. If a stock is traded under Rule 144A, we should be call it GDR rather than ADR.

I noticed that most of the DRs (all most all) traded under Rule 144A and Regulation S are GDRs rather than ADRs.

Quesion1: Why are they GDRs rather than ADRs?

Also, it seems that only non-U.S. investors can purchase Regulation S DRs. If they are sold in exchanges other than the U.S. ones and they are non-U.S. incorporated companies, why do they need to follow Regulation S of the SEC1933 Act?

Question2: why are Regulation S GDR relevant to us investors?

Thank you!