Opinion by
Mr. Justice Roberts,This is an appeal1 from the judgment of the Common Pleas Court of Dauphin County, sitting as the Commonwealth Court,2 3affirming the Board of Finance and Revenue’s settlement of appellant’s liability under the *61Corporate Net Income Tax3 for the tax year which terminated December 31, 1963.
The sole question involved here is whether appellant’s receipts from its contracts with advertisers whose advertisements were placed on outdoor billboards situated in this Commonwealth are to be regarded as “rentals . . . from property situated . . . within this Commonwealth” for purposes of the Corporate Net Income Tax.4 If the receipts are regarded as such “rentals,” the receipts must be included in the numerator of the third fraction, better known as the “gross receipts” fraction, of the formula that was employed under the Corporate Net Income Tax Act to determine the tax liability of those corporations whose entire business is not transacted in Pennsylvania.5 We believe that appellant has not met its burden of establishing the invalidity of the Board of Finance and Revenue’s settlement of its tax liability. Accordingly we affirm the order of the Common Pleas Court of Dauphin County.
Appellant and the Commonwealth submitted this ease to the court below on a stipulation of facts. That stipulation reveals that appellant owns certain road signs and leases as lessee certain other road signs [apparently referred to in the trade as bulletins] and locations therefore in Pennsylvania. Appellant, during the year in question, made contracts with advertisers *62for the placement of advertisements on billboards located in Pennsylvania. According to these contracts, appellant agreed to take all actions necessary to place and maintain the advertisements on the bulletins, including the payment of all lease rentals, taxes, and license fees.
In addition to the activities specified in the contracts, it was stipulated that appellant also performs the folloAving for its advertiser-customers:
“(a) Prepares sketches and full size samples of the proposed sign, including the idea for the arrangement of words and pictures and artwork pertaining thereto.
(b) Makes traffic surveys and recommends quantities of signs needed to give adequate advertising coverage of the advertiser’s markets Avithout oversaturation.
(c) Works with advertiser in testing the effectiveness of the media in certain markets by traffic surveys, etc.
(d) Fabricates and/or purchases the signs parts.”
It was also stipulated that: “The advertisers have no right of possession of the bulletins or signs or the land on which same were located. The sole use of the bulletins or billboards is the placement of advertisements thereon.”
Appellant contends that the receipts from its contracts Avith the advertisers are not rentals from property, but rather represent payment for services performed by the appellant in the conduct of its business. The Commonwealth, on the other hand, contends that the receipts are “rentals” from appellant’s property— i.e., appellant’s billboards. If appellant’s contention is correct, its Corporate Net Income Tax liability for 1963 will be reduced by $1,173.38.
The question of whether appellant’s receipts should be regarded as “rentals” from property or as income *63from “services” performed is not an easy one, for most business receipts represent a mixture of return for some services performed and of return on property owned. For example, a corporation that owns a large apartment building often provides to its tenants, in addition to the actual physical premises, services such as trash removal, security guards, gardening, etc. However, common sense indicates that in such a landlord-tenant arrangement the receipts from the tenants would represent primarily a return on the physical structure owned rather than compensation for services rendered as a part of the tenancy arrangement.
At the other end of the spectrum would be an accounting firm. In part the firm’s fees could be regarded as a return on its investment in its business property—i.e., the firm’s typewriters, dictaphones, office furniture, and calculators—but it is obvious that accountants’ fees represent primarily compensation for services rendered.
In the case at hand, it is clear that appellant owns certain bulletins which it makes available to its advertiser-customers. It is also clear that appellant renders certain services to advertisers such as preparing advertising copy and making market surveys. However, appellant has not offered evidence to establish that its receipts represent primarily compensation for services rendered.
It is a well-established principle of tax law that a regularly made tax assessment is presumed to be valid.6 In fact, we have specifically held that the taxpayer has the burden of showing that the Commonwealth’s computation of his Corporate Net Income Tax is incorrect. Commonwealth v. R. S. Noonan, Inc., 419 Pa. 411, 417, *64213 A. 2d 787, 790 (1965).7 Since appellant has not met its burden of establishing that its receipts represent primarily compensation for services rendered, appellant’s challenge to the tax settlement formulated by the Board of Finance and Revenue must be rejected.
The judgment of the Dauphin Common Pleas Court is affirmed.
Mr. Chief Justice Jones took no part in the consideration or decision of this case.This appeal is taken pursuant to Section 203 of the Appellate Court Jurisdiction Act of 1970, Act of July 31, 1970, P. L. 673, art. II, §203, 17 P.S. §211.203 (Supp. 1972).
The appeal to the Dauphin Common Pleas Court was filed September 22, 1967, before that court’s jurisdiction as the Commonwealth Court was assumed by the new Commonwealth Court. However, the final order of the Dauphin Common Pleas Court in this matter was not issued until August 18, 1971.
Act of May 16, 1935, P. L. 208, §§1 et seq., as amended, 72 P.S. § §3420a et seq. This act was repealed by Section 411 of the Tax Reform Act of 1971, Act of March 4, 1971, P. 1¡. 6, art. IV, §411, 72 P.S. §7411 (Supp. 1972). However, the Act of May 16, 1935, still determines liability for tax years beginning prior to January 1, 1971. See Act of March 4, 1971, P. L. 6, art. IV, §412, 72 P.S. §7412 (Supp. 1972).
Act of May 16, 1935, P. L. 208, §2, as amended, 72 P.S. §3420b, 2(c).
Id. §3420b 2(c) (3).
See, e.g., Deitch Co. v. Board of Property Assessment, 417 Pa. 213, 221, 209 A. 2d 397, 402 (1965) ; 36 P.L.E. Taxation §§242, 247.
See Commonwealth v. Hellertown Mfg. Co., 438 Pa. 134, 140-41, 264 A. 2d 382, 386 (1970) ; Commonwealth v. Stretchnit, Inc., 2 Pa. Commonwealth Ct. 270, 273-74, 273 A. 2d 750, 751 (1971).