Are you from China? I just looked this up and it seems that for Chinese nationals, O-1 is single entry. I believe it's multiple entry for nationals of nearly every other country.
It has to do with some US-China reciprocity agreement.
It has to do with some US-China reciprocity agreement.
It confused a whole lot of me the rationale behind single entry O1 visa - it does create a lot of inconvenience as we do have a subsidy in China that I'd wish to be able to travel back to.