You can work for multiple employers on an H-1B if you have multiple approved I-129 petitions. Your original comment was in regards to a transfer which falls und

You can work for multiple employers on an H-1B if you have multiple approved I-129 petitions. Your original comment was in regards to a transfer which falls under AC-21. edit: Technicalities in immigration law can have large consequences, working outside of one's status, or for an unapproved employer can result in being removed from the US and being banned from return for a number of years depending on the circumstances.