This proceeding involves separate appeals by the eight airlines named in the caption, Host International, Inc., and the City of St. Louis. The appeals were ordered consolidated by this court. They were jointly briefed and argued and will all be disposed of in this opinion. The appellants seek a review of real estate assessments for the year 1968 by the St. Louis County Assessor as affirmed by the County Board of Equalization, the State Tax Commission and the St. Louis County Circuit Court. The controversy relates to the proper method of valuation and assessment in respect to “leasehold interests” or “possessory interests” of portions of Lambert-St. Louis Municipal Airport occupied by the airlines and Host. The airport is located in St. Louis County and owned and operated by the City of St. Louis. While no tax was assessed against St. Louis City it has opposed the assessments against its lessees apparently on the theory that the added expense to its tenants would adversely affect the amount of rental they would pay the City in the future. We have appellate jurisdiction because construction of the revenue laws of this state is involved. Art. V., Sec. 3, Mo. Const.
In connection with our statement of the evidence it should be mentioned that considerable evidence was offered before the Commission to which an objection was sustained but the evidence was nevertheless heard under the provisions of Section 536.-070(7) V.A.M.S. We have considered such of that evidence as we deemed to be admissible.
The airport property embraced an area of approximately 1,700 acres and was improved with runways, taxiways, aprons, instrument landing and communication facilities and a terminal building with concourses, parking lots, cargo hangar, and office buildings.
On January 1, 1968, each of the airlines, as well as Host, occupied and paid rent on certain space in the terminal building for which they had the right of exclusive use. In addition, each airline was allocated and charged rent upon space denominated “nonexclusive space” which it was deemed to use in common with other airlines and tenants in the terminal building. As of January 1, 1968, the airlines’ use of both exclusive and nonexclusive terminal and concourse space was not the subject of formal lease agreements between them and the city; those leases had expired in 1965. As a result of negotiations between the airlines and the city commencing in the spring of 1965, formal lease agreements had been executed and submitted to the city in December, 1967. Those leases, which were for a term of 10 years commencing August 1,1965, did not become finally binding until December, 1968, when they were approved by the St. Louis City Council. It had been agreed, however, at the time negotiations began that the lease provisions and rental rates finally agreed upon would be retroactive to August 1, 1965. The rental rates paid by the airlines on both exclusive and nonexclusive space in the main terminal were as follows: Upper level, $9.00 per square foot; middle level, $6.50 per square foot; lower level, $5.50 per square foot; operating area, $3.00 per square foot; concourses, $4.00 per square foot.
*945On January 1, 1968, Host was occupying almost 32,000 square feet of space in the terminal building. This was under a concession agreement, dated January 31, 1967, under which Host was obligated to pay as rental for such space a percentage of gross annual sales on food and alcoholic beverages.
Under a separate lease, Ozark occupied an office building and hangar complex on a 10 acre site situated in the airport area. In 1968, the lease on these buildings had a remaining period of 24 years together with options for 12 and 10 year extensions. This lease was subject to cancellation by the city upon 12 months notice when, in the city’s opinion, the facilities were needed for an airport use of higher priority.
On May 31,1968, the assessor advised the airlines and Host concerning the amount of their assessments. The amount of the assessments on the space leased totaled approximately $3,000,000. In addition to that the assessor attributed to each one of them a proportionate part of a 72 acre tract called the “campus area.” A value of $1,300,000 was placed upon this campus area which, as stated, was allocated proportionately to the airlines and Host.
The formula or method used by the assessor in arriving at the foregoing valuations was obtained by him from John L. Vaughn, Jr., of Los Angeles, California, an expert in the field of real estate appraisals. On the other hand, the appellants relied upon the testimony of Walter R. Kuehnle, of Chicago, Illinois, an expert with 47 years experience in appraising real estate and interests therein. These two experts used widely differing methods in arriving at their opinions concerning the valuation of the interests here involved.
Mr. Kuehnle stated that in appraising a leasehold interest of a tenant the proper method is to determine the value of the property, the economic or rental value thereof, and the contract rental of the property as well as the length of the term of the lease and other provisions thereof which are the obligation of the lessee. He stated that “It’s a method accepted by appraisers everywhere. I know of no other way you could do it.” He further stated that by the use of this method one could determine the present value of any bonus to the lessee by the terms of the lease; that if the contractual rental was less than the fair market rental the leasehold would have a value. This method was illustrated by a simple example, as follows: If a store building being rented for $250 a month is worth $500 a month the value of the interest would be the present worth of the bonus for the remaining term of the lease. On the other hand, if the lessee was paying $750 a month for a store worth $500 a month the lease would, of course, have a negative value.
Mr. Kuehnle and his staff made an investigation of the airport properties and concluded that each of the airlines and Host were paying more than the full rental value of the areas leased by them and hence there was no bonus and the leaseholds were of no value. In arriving at the fair rental value of the space occupied by appellants, this witness not only considered the depreciated replacement value of the buildings but compared the premises with a number of other comparable airports in this country.
He further stated that California was the only state in which “possessory interests” somewhat like that used by the assessor is recognized. He also stated that the method used by the assessor resulted in a valuation of the real estate interest leased and not the leasehold interest.
Frank J. Antonio testified that on the relevant dates he was the assessor of St. Louis County; that he and his staff collected the information necessary to make the valuations in question; that they relied on the advice of John L. Vaughn, Jr. in applying the “possessory interest” method of assessing these leaseholds. He defined pos-sessory interest as representing the beneficial use of real estate by a tenant where the real estate is exempt by law from taxation as against the owner. Mr. Antonio further stated that in applying the method used in *946making the assessments he ignored the amount of rental paid by the lessee and the term that the lease would run; that he “had to in order to establish a uniform method of assessment”; that this method is applied only to tax exempt property.
The method used by the assessor is apparently new and novel. It has been formulated in an endeavor to obtain tax revenue from tax exempt real estate which, of course, must be obtained, if at all, from the tenants. We will attempt to outline this method as we understand it from reading the testimony of Mr. Antonio and Mr. Vaughn, as follows: (1) As indicated, the terms of the leases are disregarded and the assessor assumed an occupancy of 15 years for each tenant, (2) In order to obtain the estimated depreciated value of the buildings as of 1-1-68 he figured the trended replacement cost of the buildings as of 1-1-68 and depreciated it at a rate of 4% per year, (3) Using the assumed 15 year occupancy he estimated the depreciated value of the buildings on 1-1-83. The result is said to be the value of the city’s “right of reversion” on that date, (4) He next calculated the present worth of the 1-1-83 depreciated value of the buildings using a 6½% compound interest factor, (5) The present worth of the reversion (as obtained in the preceding step) is subtracted from the estimated 1-1-68 depreciated value of the buildings and the result is said to be the value of the tenant’s possessory interest in the building, (6) In regard to the 72 acre “campus area,” which was valued at $1,300,000, he calculated the present worth of the city’s reversion-ary right to the land in 15 years using a &⅛% compound discount factor of .3888. The product thus obtained was subtracted from $1,300,000, the present value, and the result was the value of the tenant’s “posses-sory interest” in the campus area, (7) The total of the value of the possessory interest in the buildings (step 5) and of the campus area (step 6) is then taken as the true value for assessment purposes and allocated to the airlines and Host in proportion to the percentage of total space occupied by each tenant on 1-1-68.
It should perhaps be mentioned at this point that complaint is made by respondents that the assessor requested copies of the leases and other information which was not furnished by some of the appellants and hence the assessor was forced to adopt a method such as outlined above in order to assess the interests. There is no merit in that suggestion. We have concluded from the record that the tenants reasonably complied with the assessor’s request. That, however, is irrelevant because it is clear from the assessor’s testimony that he would not have used the amount of rental, and length of term of the leases in any event.
The Commission made findings of fact and conclusions of law, ten pages in length. We deem it unnecessary to recite these in detail. Generally, it may be said that they were in accord with the contentions of respondents and contrary to those of the airlines and Host. It was specifically found that the method of assessment suggested by Mr. Vaughn was a “fair, reasonable, orderly, and appropriate plan of valuation”; that the opinion and testimony of Mr. Kuehnle was “not credible and without probative force.”
“In our review of the orders of the State Tax Commission we have in mind that we are not permitted to substitute our discretion for discretion legally vested in the Commission and should not set aside its findings unless such are ‘unsupported by competent and substantial evidence upon the whole record’; or are ‘for any other reason, unauthorized by law’; or are ‘arbitrary, capricious or unreasonable’; or that they involve ‘an abuse of discretion.’ ” Stein v. State Tax Commission, 379 S.W.2d 495 (Mo.1964).
We state at the outset of our consideration of this appeal that there is no controversy about the fact that this real estate, owned by the City of St. Louis, is exempt from taxation. Art. X, Sec. 6, Mo.Const. and Section 137.100(2), V.A.M.S. There *947also seems to be no question but that leaseholds in city owned real estate are taxable if they have any value. Iron County v. State Tax Commission, 437 S.W.2d 665[3] (Mo.1968).
We agree with the contention of appellants that the assessor’s valuations of their leasehold interests were arrived at by an erroneous method which directly conflicted with a method approved by decisions of this court. In Land Clearance for Redevelop. Corp. v. Doernhoefer, 389 S.W.2d 780, 784 (Mo.1965) this court stated that: “. the value of the leasehold should be determined from the testimony of qualified expert witnesses as that value which a buyer under no compulsion to purchase the tenancy would pay to a seller under no compulsion to sell, taking into consideration the period of the lease yet to run, including the unexercised right of renewal, the favorable and unfavorable factors of the leasehold estate, the location, type and construction of the building, the business of the tenant, comparable properties in similar neighborhoods, present market conditions and future market trends, and all other material factors that would enter into the determination of the reasonable market value of the property. The bonus value, sometimes referred to as the leasehold savings or profit, is the difference between the economic rental and the contract rental. The economic rental is the actual market value of the use and occupancy.” In United States v. Petty Motor Co., 327 U.S. 372, 381, 66 S.Ct. 596, 90 L.Ed. 729 (1945) the court stated: “The measure of damages is the difference between the value of the use and occupancy of the leasehold for the remainder of the tenant’s term, plus the value of the right to renew in the lease of Petty, less the agreed rent which the tenant would pay for such use and occupancy.” See also, Stephen & Stephen Properties, Inc. v. State Tax Commission, 499 S.W.2d 798 (Mo.1973).
In St. Louis County v. State Tax Commission, 406 S.W.2d 644 (Mo.1966), (a case involving substantially the same parties and issues as the one before us) we approved the Doernhoefer decision and held that the formula testified to by Witness Randall was in accord with the approved method. The Randall formula is very similar to that testified to by appellants’ expert in the case at bar. Moreover, in this prior case we expressly disapproved of a method of valuation which assumed a longer term of tenancy than the remaining life of the leases. In the case under review the Commission approved a method of valuation that assumed a 15 year tenancy which assumption squarely conflicts with our prior holding.
It is our view that there is no valid basis in law or fact for support of the method used by the assessor. As heretofore stated it disregards elements which this court has held essential in the valuation of a leasehold. Moreover, we think the practical result of the use of that method is to value a substantial portion of the real estate rather than the leasehold, which, of course, is improper and unlawful. We think one illustration of that result is shown by an old building which the assessor concluded did not have a remaining economic life of 15 years on which he assessed the entire depreciated value on 1-1-68 against the lessee. It is also interesting to note that no case has been cited in which this method has been used or approved. There is some suggestion that a similar method was approved in De Luz Homes, Inc. v. County of San Diego, 45 Cal.2d 546, 290 P.2d 544 (1955) but that case approved a different method and the factual situation is so entirely different that the case has no application to the issue before us.
The respondents seek to justify the method used by the assessor by saying that this is special use property to which the usual rules do not apply. They say there is no market for the transfer of these leases and that it is proper to assume a period of occupancy beyond the lease term because these lessees will remain in the premises for an indefinite period regardless of the lease provisions. This contention would clearly not apply to Host. While it may be likely that most of the airlines will *948continue to remain tenants in this airport we cannot approve such a speculative assumption for assessing tax valuations. We judicially know that the municipal airport in Kansas City was abandoned for major airline use a few years ago and a new airport constructed. It is also well known that there has been serious consideration for years to the establishment of another airport for the St. Louis area. Moreover, any one of the airlines might decide at any time to discontinue service to the St. Louis area. As indicated, this contention is disallowed.
In summary, we hold that the method or formula used by the assessor is an improper method of valuation unauthorized by law and that its approval by the State Tax Commission was arbitrary and unreasonable. We approve of the method of valuation outlined in our prior cases and testified to by Mr. Kuehnle.
Since there will be further consideration of these cases by the Commission there are two other contentions which should be briefly considered. Appellants complain that the Commission erred in excluding their evidence regarding rents paid at other comparable airports for space similar to that occupied by them. It is our view that such evidence was admissible. Complaint is also made that it was arbitrary and unlawful for the assessor to allocate to the appellants the value of the “campus area” which included land adjacent to the buildings in question. Respondents have not cited any authority to support that action. We are unable to see any valid basis for charging appellants with the value of land they did not lease or pay rent on and which is used by the air travel public generally.
The judgments in these cases are reversed and the causes are remanded to the trial court with directions that it reverse its judgments of affirmance and remand the cases to the State Tax Commission for further proceedings not inconsistent with this opinion.
BARDGETT, HENLEY and DONNELLY, JJ., concur. MORGAN, J., dissents in separate dissenting opinion filed. FINCH, J., dissents in separate dissenting opinion filed. SEILER, C. J., dissents and concurs in separate dissenting opinion of FINCH, J.