The US vote to adopt Open XML - IS29500 - as an American National Standard closed on evening of Wednesday 15 April.  As as result Open XML IS29500 is the newest American National Standard.

The vote was a 12 yes / 0 no / 2 abstain / 4 not yet split.  Full results can be found at http://ballot.itic.org/itic/tallyvote.taf?function=vote&committee=INCITS&ballot_id=3025&_UserReference=B1C55B9B4013124949E6A7C5