R.I. Gen. Laws § 44-13-10 — Apportionment of earnings from business partially within state

In the case of every corporation carrying on business both within and outside of this
state, its entire gross earnings from its operation for the preceding calendar year,
or for the portion of the year that the corporation has carried on business within
this state, shall be apportioned to this state as follows:
(1) In the case of an express corporation carrying on its business on steamboats, steam
or electric railroads, or street railways, and in the case of a corporation whose
principal business is a steamboat or ferryboat business as a common carrier, the total
amount of gross earnings from all sources within this state for the calendar year
or portion thereof next preceding;
(2) In the case of a common carrier steam or electric railroad or street railway corporation
a proportion as the total mileage of tracks operated by the corporation for steam
or electric railroad or street railway purposes within this state, exclusive of sidings
and turnouts, on December 31 next preceding, bears to the total mileage of tracks
then operated by the corporation for these purposes, both within and outside of this
state;
(3) In the case of any corporation operating as a common carrier dining, sleeping, chair,
or parlor car corporation, but not in the case of a public steam or electric railroad
or street railway corporation operating cars as a part of or incidental to its railroad
or railway business within this state, a proportion as the number of miles the cars
were operated in this state during the year ending December 31 next preceding bears
to the total number of miles the cars were then operated for these purposes both within
and outside of this state;
(4) In the case of a public service telegraph, cable, or telecommunications corporation,
or corporation which is manufacturing, selling, distributing and/or transmitting to
the public currents of electricity to be used for light, heat, or motive power, the
total amount of gross earnings within this state for the calendar year; provided,
however, that gross earnings from providing mobile telecommunications services shall
be apportioned to this state where the customer’s primary place of use, as determined
in accordance with the mobile Telecommunications Sourcing Act (4 U.S.C. §§ 116 — 126), is within this state.
(5) In the case of a corporation whose principal business is manufacturing, selling and/or
distributing to the public illuminating or heating gas or water, a proportion as the
total miles of mains operated by the corporation within this state on December 31
next preceding bears to the total mileage of mains or wires operated by the corporation
both within and outside of this state;
(6) In any case to which these proportions are not equitably applicable, in the proportion
that is equitable.