Lesson 2 of 3 Math checked Facts checked against sources on 16 June 2026 14 min

Property owner economics: lease decisions, interest rates and debt

Net effective rent, why renewing a tenant often beats a higher headline rent, how rising rates hit income and value at once, and how REIT payout rules shape funding.

Industry brief, with a one-minute summary: Property owners and REITs

Key takeaways

An owner has two scorecards. Income: rent collected minus running costs and interest, which pays investors every quarter.
Owners often prefer more rent-free months to a lower headline rent, because the headline rent is what valuers and buyers compare across buildings.
Value is NOI divided by the cap rate. If NOI rose and value fell, the cap rate must have risen, which usually follows interest rates.

Key idea

An owner has two scorecards. Income: rent collected minus running costs and interest, which pays investors every quarter. Value: income divided by the yield buyers want, which decides how much the owner can borrow and what its shares are worth. Leasing decisions move income; interest rates move both, because they raise the cost of debt and the yield buyers want at the same time.

Empty space is expensive. While a floor is empty the owner loses the rent, pays the service charge and taxes on it, and often must refurbish and offer months of free rent to the next tenant. So the useful number is not the headline rent but the net effective rent: the total rent over the lease after incentives, empty months and refurbishment, spread over the years and the space.

Worked case

Renew the tenant or re-let the floors? An office lease decision

The prompt

Mainbrook Offices (a fictional owner in Frankfurt) has a tenant on 10,000 square metres whose lease ends this year. Option A: renew for 5 years at EUR 400 per square metre a year, with 6 months rent free. Option B: let the tenant go, refurbish for EUR 2 million, and re-let after 12 months empty at EUR 450, with 9 months rent free on a 4-year lease. While empty, the owner pays EUR 50 per square metre in service charges and taxes. Over the same 5 years, which option brings in more?

Open this case to practice it with a partner

The structure

Net income over five years = rent paid minus rent-free months, empty costs and refurbishment
- Option A: rent for 5 years minus 6 months free
- Option B: 12 months empty, then 4 years of rent minus 9 months free, minus refurbishment and empty costs
- Net effective rent: net income per square metre per year
- Risks: how long the space really stays empty, and the signal a lower rent sends

Working it through

1. Option A income
10,000 square metres x EUR 400 x 5 years, minus 6 months free.
Option A net rent over 5 years (EUR million):(10,000 × 400 × 5 - 10,000 × 400 × 0.5) ÷ 1,000,000 = 18
2. Option B rent
10,000 square metres x EUR 450 x 4 years, minus 9 months free.
Option B rent after rent-free months (EUR million):(10,000 × 450 × 4 - 10,000 × 450 × 0.75) ÷ 1,000,000 = 14.63
3. Option B net income
Take off EUR 2 million of refurbishment and EUR 0.5 million of costs while empty.
Option B net income over 5 years (EUR million):14.625 - 2 - 10,000 × 50 ÷ 1,000,000 = 12.13
4. Net effective rent, Option A
EUR 18 million over 10,000 square metres and 5 years.
Net effective rent A (EUR per square metre a year):18,000,000 ÷ (10,000 × 5) = 360
5. Net effective rent, Option B
EUR 12.125 million over the same space and years.
Net effective rent B (EUR per square metre a year):12,125,000 ÷ (10,000 × 5) = 243

The recommendation

Mainbrook should renew the tenant, because Option A earns EUR 18 million over five years, or EUR 360 per square metre a year, against EUR 12.125 million, or EUR 242.50, from re-letting at a higher headline rent. First, a year of empty space costs both the lost rent and EUR 0.5 million of charges the owner must pay itself. Second, the higher EUR 450 headline is eaten by 9 months rent free and the EUR 2 million refurbishment. The risk is that renewing at EUR 400 sets a lower rent level that buyers and valuers will see, and that the tenant may still leave in five years. As a next step, offer the renewal with a rent review in year three, and check how long similar floors in Frankfurt have stayed empty.

Risks: Valuers often quote the headline rent rather than the net effective rent; A shrinking tenant may want less space at the next renewal.

Why owners protect the headline rent

Owners often prefer more rent-free months to a lower headline rent, because the headline rent is what valuers and buyers compare across buildings. Two leases can have the same headline rent and very different net effective rents. In a case, always ask for incentives and empty periods, not only the rent.

Interest rates: one move, two hits

US 10-year government bond yield, yearly average (percent)(%)

So-what

When the risk-free rate tripled from 2021 to 2023, buyers wanted higher yields from property too. US listed REITs lost about 25 percent in 2022 (FTSE Nareit All REITs, total return), against about 18 percent for the S&P 500.

Higher rates hurt owners twice. Income falls as debt is refinanced at higher interest. Value falls because buyers want a higher cap rate (the yearly income as a share of the price), and value is income divided by the cap rate. Lower value raises loan to value even if no new debt is taken on, and lenders and regulators set limits on it. In Singapore, the Monetary Authority of Singapore caps REIT borrowing at 50 percent of assets and requires income of at least 1.5 times interest, rules it set in November 2024.

Worked case

A Singapore logistics REIT refinances its debt at a higher rate

The prompt

Quaystone Logistics REIT (fictional, listed in Singapore) earns net operating income (NOI) of SGD 200 million a year. It has SGD 1,500 million of debt at 3 percent, and management and trust costs of SGD 15 million a year. The debt must be refinanced at 5.5 percent, and buyers now value warehouses at a 5.5 percent cap rate instead of 5 percent. What happens to funds from operations (FFO), which funds the payout, and to debt as a share of portfolio value, which Singapore caps at 50 percent?

Open this case to practice it with a partner

The structure

Two effects of higher rates: on cash income and on asset values
- Income: FFO = NOI minus interest minus management and trust costs
- Value: portfolio value = NOI divided by the cap rate
- Gearing: debt divided by portfolio value, against the 50 percent cap
- Options: sell assets, issue new units, or raise NOI

Working it through

1. Interest today
3 percent of SGD 1,500 million.
Interest at 3 percent (SGD million):1,500 × 0.03 = 45
2. FFO today
NOI minus interest minus management and trust costs.
FFO today (SGD million):200 - 45 - 15 = 140
3. FFO after refinancing
Interest at 5.5 percent is SGD 82.5 million.
FFO after refinancing (SGD million):200 - 1,500 × 0.055 - 15 = 103
4. Fall in FFO
The drop as a share of today's FFO.
Fall in FFO (fraction):(140 - 102.5) ÷ 140 = 0.2679
5. Portfolio value at the new cap rate
NOI divided by 5.5 percent, against SGD 4,000 million at 5 percent.
Portfolio value at 5.5 percent (SGD million):200 ÷ 0.055 = 3,636
6. Debt as a share of value
SGD 1,500 million over the new value, against 37.5 percent before.
Gearing after the cap rate move (fraction):1,500 ÷ (200 ÷ 0.055) = 0.4125

The recommendation

Quaystone should plan for a payout about 27 percent lower and start cutting debt now, because refinancing at 5.5 percent takes FFO from SGD 140 million to SGD 102.5 million while gearing rises from 37.5 to 41.25 percent with no change in rent. First, interest is the only line that moved, so cost cuts elsewhere cannot fill a SGD 37.5 million gap. Second, at 41.25 percent the REIT is still under the 50 percent cap, so it has time to sell an older warehouse or two near book value and repay debt. The risk is selling into a weak market, or issuing units below their asset value, which hurts existing unitholders. As a next step, list the leases expiring in the next two years and their rent gap to market, because raising rents on renewal is the cheapest way to rebuild FFO.

Risks: A further rise in cap rates would cut values again; Units may trade well below asset value, making new equity expensive.

Payout rules shape how REITs grow. A US REIT must pay out at least 90 percent of its taxable income, and a Singapore REIT must distribute at least 90 percent to keep its tax treatment, so neither can keep much cash. Growth is funded with new debt and new shares, which works when shares trade above asset value and borrowing is cheap, and stalls when they do not.

Timed math drill

AvalonBay's same-store apartments earned residential revenue of USD 2,712.1 million in 2025 and NOI of USD 1,860.4 million. What was the NOI margin, as a decimal? (Round to three decimals.)

Timed math drill

An office lease in Bengaluru starts at INR 100 per square foot a month and rises 15 percent every three years. What is the rent in year 7, after two increases, in INR? (Round to two decimals.)

Check your understanding

A REIT's value fell 10 percent this year, but its NOI rose 2 percent. What most likely happened?

Terms in this lesson

NOI (net operating income)Cap rate (capitalization rate)Loan-to-value (LTV)REIT (real estate investment trust)Cost of capital (WACC)Discount rate and hurdle rate Sensitivity analysis Opex (operating expenses)

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It builds on what you just read, in Real estate operators: REITs, offices, warehouses and rental homes.

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