8.3 Proration, Transfer Tax, and Investment Math

Key Takeaways

  • Prorations divide an annual cost between buyer and seller based on the closing date and who owes which days.
  • The seller typically owes expenses through the day of closing; confirm the method the question states.
  • Transfer tax equals the taxable amount divided by the stated increment, times the rate per increment.
  • Capitalization rate equals net operating income divided by value: Value = NOI / Cap Rate.
  • Gross rent multiplier equals price divided by gross rent and is a quick, expense-blind screening tool.
Last updated: June 2026

Proration Basics

Proration fairly splits annual costs, mainly property taxes and prepaid items, between buyer and seller at closing. Two conventions appear on the exam:

  • Statutory (banker's) year: 360 days, 30 days per month. Easiest math and most common on tests.
  • Actual (calendar) year: 365 days. Used when a question says to count exact days.

The seller usually owes costs through the day of closing, and the buyer owes from the day after. Always determine: the daily rate, the number of days each party owns, and whether the item is a debit or credit.

Worked Tax Proration

Annual taxes of $3,600 are unpaid; closing is June 30 using a 360-day year. The seller owes January 1 through June 30 (6 full months).

  1. Monthly tax = $3,600 / 12 = $300.
  2. Seller's share = $300 x 6 = $1,800.

Because the taxes are unpaid, the seller's $1,800 is a debit to the seller and a credit to the buyer; the buyer will pay the full bill later but was reimbursed at closing. If the seller had already prepaid the year, the direction reverses and the buyer reimburses the seller for days after closing.

Test Your Knowledge

Annual property taxes are $4,800 and unpaid. Using a 360-day year, closing occurs on April 30 (seller responsible through closing). What is the seller's prorated share?

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B
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D

Transfer Tax

Transfer (or conveyance) tax is charged per a fixed increment of the sale or consideration. The formula is: Tax = (Taxable Amount / Increment) x Rate per Increment. A common increment is $500.

Example: A sale price of $325,000 at $0.50 per $500.

  1. Number of increments = $325,000 / $500 = 650.
  2. Tax = 650 x $0.50 = $325.

Watch the increment: $1.10 per $1,000 on the same $325,000 = 325 increments x $1.10 = $357.50. Read whether any existing assumed mortgage is excluded from the taxable amount, as some jurisdictions tax only new money.

Investment Math

Income-property questions convert rent into value. Build the income statement first, then apply a formula.

TermDefinition
Gross IncomeAll potential rent
NOIGross income minus operating expenses (not debt service)
Cap RateNOI / Value
GRMPrice / Gross (annual or monthly) Rent

Key rearrangements: Value = NOI / Cap Rate and NOI = Value x Cap Rate.

Example: A building nets $48,000 NOI and investors want an 8% cap rate. Value = $48,000 / 0.08 = $600,000. Lowering the required cap rate to 6% raises value to $48,000 / 0.06 = $800,000, showing value and cap rate move inversely.

Gross Rent Multiplier

GRM is a fast screening tool that ignores expenses. GRM = Price / Gross Rent. To value a property, multiply: Value = Gross Rent x GRM.

Example: Comparable fourplexes sell at a GRM of 110 on monthly gross rent. A subject property collects $4,200 per month.

  • Value = $4,200 x 110 = $462,000.

Because GRM skips operating expenses, never confuse it with the cap-rate approach. A high-expense building can show an attractive GRM yet a poor cap rate, which is exactly the distinction the exam tests.

Test Your Knowledge

An apartment building generates $72,000 in net operating income. An investor requires a 9% capitalization rate. What is the indicated value?

A
B
C
D

Insurance, rent prorations, and the equity build-up idea

Prorations are not limited to taxes. Prepaid homeowner's insurance, HOA dues, and collected rent are split the same way, but the debit/credit direction depends on who prepaid. If a seller prepaid a $1,200 annual policy and closes after 4 months, the seller has 8 unused months coming back: $1,200 / 12 = $100/month x 8 = $800 credited to the seller, debited to the buyer (if the policy transfers).

Worked example: rent proration on a rental purchase

A duplex generating $2,400/month in rent closes on the 10th, and the seller already collected the full month. Using a 30-day month, the buyer owns days 11–30 = 20 days.

  1. Daily rent = $2,400 / 30 = $80.
  2. Buyer's share = $80 x 20 = $1,600, credited to the buyer and debited to the seller (the seller holds rent for days the buyer will own).

Equity, appreciation, and return

ConceptFormula
EquityMarket value − loan balance
Appreciation rate(New value − Old value) / Old value
Cash-on-cash returnAnnual cash flow / cash invested

Example: A property bought for $250,000 is now worth $300,000. Appreciation = ($300,000 − $250,000) / $250,000 = 20% total. If held 4 years, that is roughly 5% simple per year — the exam usually wants the total unless the item asks for an annual figure.

Profit, loss, and the percent-of-cost trap

Investment items also test simple profit and loss on a sale, and the exam plants its trap in the base of the percentage — profit percent is figured on the original cost, not the sale price.

Worked example: percent profit

An investor buys at $180,000 and sells at $216,000.

  1. Profit = $216,000 − $180,000 = $36,000.
  2. Percent profit = $36,000 / $180,000 = 20% (base = cost, not the $216,000 sale price).

Worked example: working backward from a loss

A property sells for $171,000, which represents a 10% loss. Find the original cost.

  1. Sale = cost x (100% − 10%) = cost x 0.90.
  2. Cost = $171,000 / 0.90 = $190,000.

The trap answer adds 10% to $171,000 ($188,100), under-stating the cost because the 10% should be taken on the larger original figure.

QuantityFormulaBase
Percent profitProfit / costOriginal cost
Percent lossLoss / costOriginal cost
Sale priceCost x (1 ± rate)Original cost

Whenever a percentage of gain or loss appears, ask "percent of what?" — the answer on these problems is almost always the original purchase price.