GeoMetrics

This is an appeal by the County of Santa Clara from a summary judgment ordering the refund of property taxes collected from respondent, GeoMetrics. As refined by stipulation, the sole question on appeal is whether the County may impose an unapportioned ad valorem property tax upon aircraft owned by a corporation domiciled in the county, but located physically in foreign countries and engaged in foreign commerce for all or a portion of the tax year. We hold that such an unapportioned tax is barred by the commerce clause of the federal Constitution, and affirm.

Factual and Procedural Background

The facts as stipulated disclose that respondent, a California corporation with its principal place of business in Santa Clara County, provides airborne geophysical surveys to locate subsurface mineral deposits throughout the world. The properties in issue are two aircraft, Navajo I and Navajo II.

Navajo I, acquired in January 1973, was present in the county to early June of 1973. Between June and October, the aircraft was sporadically within the county and other states. However, from October 1973 to October 1977, Navajo I was outside the United States altogether, located for the…