Sole Trader or Limited Company? When Switching to an SL Actually Pays Off

It’s one of the questions we hear most from self-employed professionals once their business starts picking up speed: is it worth setting up a limited company (SL), or should you keep filing as a sole trader? The honest answer is almost never the one you’ll find in forums or YouTube videos (“once you clear €40,000 in profit, it’s already worth it”). It depends on your actual profit, your region, whether you need to draw money out of the company to live on, and costs that people tend to forget when they run the numbers.

Personal income tax vs. corporate tax: the comparison that actually matters

As a sole trader, your profit is taxed under personal income tax (IRPF), lumped in with any other income you earn, and on a progressive scale: the more you make, the higher the marginal rate applied to the top slice of your profit. In the upper brackets, that marginal rate can approach or even exceed 45-47% depending on your region, since part of personal income tax is devolved to Spain’s autonomous communities, each of which sets its own brackets.

A limited company, by contrast, pays Corporate Tax at a flat rate (with a reduced rate typically available to newly incorporated companies during their first profitable years, and different rates for certain small or micro businesses depending on turnover). Here’s the nuance almost nobody explains properly: that flat rate only applies to profit that stays inside the company. If you then want to take that money into your own pocket, you’ll have to do it either through a director’s salary (which is taxed again under your personal income tax) or through dividends (taxed as savings income when distributed). Comparing “sole trader income tax” against “SL corporate tax” only holds up if you leave the profit inside the company, reinvested. The moment you need that money to live on, you have to factor in the second layer of taxation before drawing any conclusions.

The hidden costs of setting up an SL that nobody mentions

The theoretical tax saving can be entirely eaten up by costs that simply don’t exist when you’re self-employed. Incorporating a company involves notary and Companies Registry fees. Then come the recurring ones: mandatory double-entry bookkeeping (versus the simpler records a sole trader keeps), annual filing of accounts with the Companies Registry, greater complexity — and cost — from your accountant, and the obligation to keep formal accounts even if the business is small. On top of that, as a director you’re normally still required to pay self-employed social security contributions (RETA) — having an SL doesn’t make those go away, except in very specific cases — so it’s not unusual to end up paying both a self-employed contribution and company running costs at the same time. There’s also less flexibility: the SL’s money belongs to the SL, not to you, and taking it out without following the proper procedures (poorly documented shareholder loans, personal expenses booked as company expenses) is exactly what triggers tax office adjustments down the line.

The “€40,000 and it’s already worth it” myth

That figure gets repeated as if it were a law of physics, but it’s a dangerously oversimplified one. It only compares the marginal personal income tax rate against the corporate tax rate, without accounting for the SL’s structural costs, whether you’ll need to draw the money out to live on (which means paying tax again when you do), or your personal circumstances (deductions, other income, region). For a sole trader earning €40,000 who needs that full amount to cover their mortgage and everyday expenses, setting up an SL could end up costing more than staying as they are, because in practice they’d have to withdraw nearly all the profit and pay tax twice. An SL genuinely starts to make sense when there’s recurring profit that doesn’t need to be withdrawn in full, when you want to reinvest inside the company (buying another business, assets, growing the team), when there are partners or investors involved, or when limited liability towards third parties outweighs the tax saving. There’s no magic number — there’s a calculation, done company by company, with your real profit, your personal cash-flow needs and your region on the table.

At Zythos Business, we don’t sell the SL as a product or recite the €40,000 rule: we sit down with each self-employed professional and each small business to run that comparison against their real numbers — profit, need to withdraw cash, structural costs — before recommending the leap. And if the switch does pay off, we handle the whole process alongside you: incorporation, tax registration, first set of accounts, and the obligations that follow, so the decision gets made on data, not myths.