If you have been employed continuously for at least one out of the last three years by a foreign company related in ownership to a U.S. company (parent, branch, affiliate or subsidiary), you may qualify for the L-1 visa. This one-year of continuous employment must have been served outside of the United States. However, under certain circumstances, some time spent in the U.S. will not interrupt the one year requirement.
With the L-1 visa, you are seeking to enter the United States temporarily in order to continue working for the same employer, affiliate or subsidiary or to use the L-1 visa to establish a new U.S. affiliate, subsidiary, or branch. One of the many benefits of the L-1 visa, however, is that you are permitted to simultaneously apply for a Green Card. This makes the L-1 a dual-intent visa.
Full-time employment for the U.S. company is not required, but as an L-1 visa holder, you are expected to commit a significant portion of your time to your employer on a regular basis. Also, you must continue to work in a managerial or executive capacity (L-1A managers and executives) or in a position involving specialized knowledge (L1-B specialized knowledge personnel).
And keep in mind this major benefit–if you fall within the L-1A managers and executives category and want to apply for a Green Card, the processing and waiting times are much quicker than for those in other employment-based Green Card categories.