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THE SUPREME COURT OF NEW HAMPSHIRE
___________________________
Merrimack
No. 97-779
CATERPILLAR INC. & a.
v.
NEW HAMPSHIRE DEPARTMENT OF REVENUE ADMINISTRATION & a.
October 25, 1999
Rath, Young, and Pignatelli P.A., of Concord (William F.J. Ardinger and Brian T. Tucker on the brief), Morrison & Foerster, LLP, of New York, New York (Paul H. Frankel and Craig B. Fields on the brief, and Mr. Frankel orally), Sutherland, Asbill & Brennan, of Washington, D.C. (Jerome B. Libin on the brief), and Daniel J. Schlicksup, of Peoria, Illinois, by brief, for the plaintiffs.
Philip T. McLaughlin, attorney general (Martin P. Honigberg, senior assistant attorney general, on the brief and orally), for the defendants.
Peter S. Garre, of New London, by brief, as amicus curiae.
HORTON, J. The plaintiffs, Caterpillar Inc. and two of its subsidiaries, Caterpillar Financial Services Corporation and Solar Turbines Incorporated, appeal a Superior Court (McGuire, J.) order granting the cross-motion for summary judgment of the defendants, the State Department of Revenue Administration and its commissioner, in an action challenging the constitutionality of certain provisions of RSA chapter 77-A (1991 & Supp. 1998). We affirm.
Caterpillar Inc. is a multinational corporation headquartered in Peoria, Illinois. In each of the tax years at issue, Caterpillar Inc. owned over fifty domestic and foreign subsidiaries and several foreign affiliates. Caterpillar Inc. and all of its subsidiaries engaged in one unitary business. See RSA 77-A:1, XIV. Only the plaintiffs, however, conducted business in New Hampshire and were thus required to file tax returns on their business profits pursuant to RSA chapter 77-A. See RSA 77-A:2 (1991) (amended 1993).
In 1991, the State Department of Revenue Administration (department) audited the plaintiffs' 1987, 1988, and 1989 New Hampshire tax returns and issued a notice of assessment, demanding additional business profits tax payments. The department ordered the plaintiffs to remit the taxes due on royalties and interest received by Caterpillar Inc. from various foreign subsidiaries and affiliates from 1987 through 1989, amounts which the plaintiffs had failed to include as income in their returns. The plaintiffs filed a protest with the department in September 1991, arguing, inter alia, that the manner in which the foreign interest and royalty payments had been taxed violated the Commerce Clause of the Federal Constitution, see U.S. CONST. art. I,