H-1B aliens may only work for the petitioning U.S. employer and only in the H-1B activities described in the petition. The petitioning U.S. employer may place the H-1B worker on the worksite of another employer if all applicable rules of the Department of Labor and USCIS are followed. H-1B aliens may work for more than one U.S. employer, but must have a petition approved for each employer.
Period of Stay
A foreign worker with an H-1B visa can stay in the U.S. for a maximum of six years (plus extensions in certain circumstances) period. The H-1B visa is initially valid for three years and can then be extended for another three years.
Even though the H-1B visa is a non-immigrant visa, it is one of the few visa categories recognized as dual intent, meaning an H-1B holder can have legal immigration intent (apply for and obtain a Green Card) while still a holder of the visa. There is no presumption that H1-B holder is an immigrant; no requirement to enter ”temporarily” or have a residence abroad which he or she has no intention of abandoning; and filing of immigrant petition or other indication of seeking permanent residence is not evidence of abandoning foreign residence for purposes of seeking or maintaining H-1B status. This distinction from other nonimmigrant visas is very important for H-1B nonimmigrant while applying for certain immigration benefits.A U.S. employer may obtain permanent residence (Green Card) status for an H-1B alien if the employer can demonstrate that it is unable to locate a U.S. worker to fill the position.