Should I Buy a Rental? Personal vs Company, and the Bet You're Really Making

This article represents a personal view and is not tax or financial advice. Landlord taxation is complex and changes often; the figures here are illustrative and use assumed rates, so verify current rules and speak to a qualified accountant before deciding.

The pitch for buy-to-let is seductive: buy a flat, let it out, collect rent while it quietly grows in value. Passive income and capital growth, both at once. The reality is more demanding and more honest than the pitch, and it is worth seeing clearly before you tie up a deposit and take on a mortgage in someone else's home.

It is not passive income

A rental is a small business. There are tenants to find, reference and manage; maintenance and repairs that arrive on their own schedule; gas and electrical safety certificates; insurance; void periods with no rent but a mortgage still due; the occasional arrears or dispute; and a tax return every year, with more paperwork still if you run it through a company. You can pay a letting agent to take some of it, but that is another slice of the rent gone. Calling it passive sets you up to be surprised.

The yield is thinner than it looks

Gross yield (rent over price) always looks fine. It is what survives costs, the mortgage and tax that matters, and that number is often small. For a higher-rate taxpayer with a decent-sized mortgage it can be negative, because of a rule called Section 24: held personally, you can no longer deduct your mortgage interest as an expense. You get a flat 20% tax credit on it instead, which does not go far when your own tax rate is 40% or more.

The dashed line is break-even. Notice where the personal line crosses it: a 40%-rate landlord on a normal mortgage rate can be paying to hold the property, not being paid to. That is no freak case. It is the ordinary arithmetic of Section 24 meeting a mid-single-digit interest rate.

Personal versus company: the tax fork

This is why so many landlords now buy through a limited company. A company is not caught by Section 24: it deducts the mortgage interest in full and pays corporation tax on the real profit. The catch is getting the money out. Taking it as a dividend means dividend tax on top of the corporation tax already paid, so the same profit is taxed twice. Left inside the company to buy the next property, it is taxed once.

• A company tends to suit a higher-rate taxpayer building a portfolio and reinvesting the profits rather than spending them.
• Holding personally is simpler and often fine for a basic-rate taxpayer, or where you want the income in your pocket now.
• A company is not free: accountancy, filing, and often a higher mortgage rate on limited-company lending eat into the saving. Run your own numbers before assuming it wins.
• Moving a property you already own personally into a company is a sale in the eyes of the taxman, with potential capital gains tax and stamp duty to pay, so the structure is far easier to choose at the start than to change later.

The bet is capital growth, not rent

Here is the part the yield conversation buries. On realistic numbers the net rental income is a sliver. Sometimes it is a negative one. Almost all of the money made in buy-to-let, historically, has come from the property itself rising in value, magnified by the mortgage. That is a real way to build wealth. But it is a bet on the housing market continuing to rise, not a yield you are being paid.

Two things follow from that chart. First, if you are buying for income, buy-to-let may disappoint, because the income is thin. Second, if you are buying for the capital growth, be honest that you are making a leveraged bet on house prices, and leverage cuts both ways: the same mortgage that magnifies a rise magnifies a fall, and property is illiquid and concentrated. One asset, one street, one market. A diversified investment can be sold in a day; a flat cannot.

So should you?

Go in clear-eyed about what it is: a part-time business, a thin or negative income, a leveraged bet on house prices, and a real tax decision between personal and company. On those terms, buy-to-let can still be a sound way to build wealth for the right person. The mistake is buying the passive-income story and being blindsided by the business, the tax and the fact that your return is riding on the market. Decide which bet you are actually making before you make it.

The numbers swing hard with the mortgage rate and your own tax position, so it is worth putting your own in. The buy-to-let calculator compares the net income personally versus through a company, and shows how much of the return is really capital growth.