The purpose of Form I-129S is for an employer to classify an employee as L-1 non-immigrant and applies only to intra-company transferees under a blanket L-petition approval. Only an employer who has already obtained approval of a blanket L-1 petition may file this form to classify employees outside the United States as executives, managers, or professionals with specialized knowledge.

Form I-129S must be filed with all of the same evidence that was filed initially. Any foreign language documents filed with Form I-129S must also have a full English translation which a translator has certified as complete and correct. The translator must also certify on Form I-129S that he or she is competent to translate the foreign language document into English.

Initial evidence required for Form I-129S includes: 1) a copy of the approval notice for the blanket L petition; 2) a letter from the foreign employer detailing his or her dates of employment, job description, qualifications and salary. The letter from the employer must also indicate that the alien has worked for the employer for at least one continuous year in the three year period before the filing of Form I-129S. The alien must have worked in a managerial, executive, or professional capacity utilizing specialized knowledge. If the alien is claiming employment as a professional with specialized knowledge, he or she must include with Form I-129S a copy of a U.S. Degree, or a foreign degree which is the equivalent of a U.S. Degree. If the alien does not have a degree, Form I-129S requires that the alien provide evidence which show that he or she has education and or experience that is the equivalent to a U.S. Degree.