The L-1 visa is for an intra-company transferee, who has worked for a company abroad in an executive, managerial, or "specialized- knowledge" capacity for at least one year within the three years prior to coming to the U.S. and is coming to the U.S. to work for a related (parent, subsidiary, affiliate, or branch) company in one of those three types of positions. The L-1A Visa is for executives and managers, while the L-1B Visa is for transferees with specialized knowledge.
L-1 requirements
In order to sponsor an application for an L1 visa:
A foreign parent must own at least 50% of a US subsidiary, and have veto powers over the subsidiary's actions;
A US parent must own must own at least 50% of the foreign subsidiary, and have veto powers over the subsidiary's actions;
Affiliate US and foreign companies must each be at least 50% owned by the same ultimate parent;
A US organization with a branch office abroad qualifies, as does a foreign organization with a US branch (though this must be more than simply an agent or representative);
A US organization which employs e.g. sales personnel overseas can sponsor such employees for L1's even if there is no non-US office.
The maximum stay is 7 years for managers and executives and a 5 years for specialized knowledge. Any period of time in the U.S. on H1B status is usually counted against these L-1 limits and vice versa.
L-2 requirements
L-2 Visas are for the spouse and children of L-1 visa holders who wish to visit or accompany the principal visa holder in the U.S.
For more information, or for help determining and obtaining the right VISA for you, please consider a legal consultation.