In a recent liaison meeting with AILA, the USCBP Buffalo, NY office clarified that where a TN visa applicant is seeking entry to perform work for a U.S. affiliate of his/her Canadian employer, it is acceptable for an official of the Canadian employer to sign the individual’s TN support letter.  AILA/CBP Buffalo, AILA InfoNet Doc. No. 14020748 (posted 2/7/14).