The purchase price is the smaller commitment. Every timeshare carries an annual assessment, usually called a maintenance fee, which funds the resort's operating costs, insurance, taxes and reserves. It is due whether or not the owner uses the week, it generally rises over time, and it continues for as long as the interest is held. Where the resort faces a cost larger than its reserves, the shortfall is billed as a special assessment, in the same way it is in any common-interest community. Because the price is paid once while the assessment recurs and rises, the assessments can come to exceed the purchase price over a long holding period, which is why any comparison that looks only at the price is measuring the wrong thing.
The body that levies them is recognized in the tax code. IRC 528 defines a "timeshare association" alongside condominium and residential real estate management associations, as an organization whose members hold timeshare rights to use, or timeshare ownership interests in, association property. The elective regime that provision creates, and the rate that goes with it, belong with homeowners associations generally.
One federal consumer-protection rule expressly does not reach timeshare financing, and it is the one most people would assume applies. Regulation Z's ability-to-repay requirement, at 12 CFR 1026.43, obliges a creditor to make a reasonable and good-faith determination that a borrower can repay before making most closed-end mortgage loans. Its scope provision excludes "a mortgage transaction secured by a consumer's interest in a timeshare plan, as defined in 11 U.S.C. 101(53(D))." So a loan taken at a sales presentation to buy a timeshare sits outside that determination by rule, not by oversight. That is a fact about how the product is financed, and it belongs in any assessment of it alongside the price and the fee.
The tax code treats a timeshare more generously than most people expect, in one direction only. Publication 936 states that "you can treat a home you own under a time-sharing plan as a qualified home if it meets all the requirements," describing a time-sharing plan as an arrangement between two or more people that limits each person's interest in the home, or right to use it, to a certain part of the year. So interest on debt secured by a qualifying timeshare can be qualified residence interest, subject to the same limits that apply to any second home. The publication adds a condition for owners who rent out their week: "If you rent out your time-share, it qualifies as a second home only if you also use it as a home during the year," and days of use and rental are counted only during the period the owner has a right to use the property or to receive benefits from renting it. Whether a timeshare is a "second home" in any other rulebook, particularly a mortgage lender's, is a separate question with a different answer.
Developer financing is structurally normal here for a reason written into the tax code. The installment method is generally unavailable on a dealer disposition, which would otherwise force a seller of inventory to report the whole gain in the year of sale. IRC 453(l)(2)(B) carves out dispositions in the ordinary course of business, to an individual, of a timeshare right to use or ownership interest in residential real property for not more than six weeks a year, provided the seller elects to pay interest on the deferred tax under the accompanying provision. In plain terms, Congress preserved installment reporting for timeshare sellers on stated conditions, which is part of why in-house financing at the point of sale is the industry norm rather than the exception.
What a timeshare is not is an income-producing asset. Nothing in the structure generates a return to the owner. It converts money into future occupancy, and the only ways to realize value from it are to use it, to exchange it, or to rent it out, the last of which carries the tax condition above. Reselling requires finding a buyer for an interest that carries a perpetual bill with it, and an owner who cannot use the week still owes the assessment. That asymmetry, obligations that continue and rights that expire annually if unused, is the defining feature of the product and is the thing to weigh before buying. A separate industry has grown up around owners who want out, and it has its own hazards.