INA § 101(a)(15)(L), 8 CFR § 214.2(l)

An Intracompany Transferee. . .

The employee must have worked abroad for the foreign company for a continuous period of ONE YEAR in the preceding THREE YEARS.

. . . between qualifying companies. . .

The foreign company for which the employee has worked for at least one year abroad must possess shared ownership with the sponsoring U.S. company in a specific manner recognized by U.S. business laws.

. . . during the entire period of stay in the U.S. . .

Both foreign and U.S. companies must be qualifying organizations that are actively engaged in business during the ENTIRE PERIOD of employee assignment to the U.S.

. . .who was employed abroad in a specialized capacity. . .  

The employee to be transferred must have been employed abroad in an EXECUTIVE or MANAGERIAL position (L-1A) or a position requiring SPECIALIZED KNOWLEDGE (L-1B).

. . . is assigned to the U.S. company to perform in a specialized capacity. . .

The employee must be coming to the U.S. company to fill one of these positions, and continue to engage in executive, managerial or specialized knowledge activities in a REGULAR and SYSTEMATIC MANNER during the entire duration of L visa status.

. . . and is qualified for the position.

The employee must be qualified for the executive, managerial or specialized knowledge position by virtue of his or her PRIOR EDUCATION and EXPERIENCE.

Corollary Benefits:

Immediate family members of the principal L-1 beneficiary are automatically accorded L-2 status, and may study in the U.S.  Spouses of L-1 visa holders may qualify for employment authorization while in the U.S. in L-2 status.

Duration of stay is initially granted for three years max (one year for new U.S. operations) and extendable to 5 years max for L-1Bs (specialized knowledge employees) and 7 years max for L-1As (executives and managers).

L-1A visa holders typically qualify for the Employment-Based First Preference (EB-1) in employer-sponsored applications for permanent residence, thus avoiding labor certification and greatly shortening the process.