Having several companies doesn't lower your taxes: the right structure does (and here's how to build it)

It's one of the most common questions from the business owner who has grown: "I have three businesses — should I have three companies?" And the honest answer is the one that sells the least: neither the number of business lines nor the number of companies saves you a single peso. Legal entities pay a flat 30% ISR (art. 9 LISR) — dividing one profit among three companies produces exactly the same tax as leaving it in one. What does produce efficiencies, and large ones, is the architecture: which activity lives in which entity, how they finance each other, and where each peso flows.

The right question isn't how many companies, but what lives together and what lives apart

There are three separation criteria that do have economic logic — and therefore a defense. First, risk: the line with employees, trucks on the highway or liability toward clients should not share quarters with the group's valuable assets; if a lawsuit or a tax assessment hits the operating company, it shouldn't drag down the rest. Second, the VAT profile: if you mix taxable activities with exempt activities in the same entity, your creditable VAT gets prorated (arts. 5 and 5-A LIVA) and you start losing the credit on expenses that were 100% recoverable — separating the exempt line from the taxable one cleans up the whole mechanic. Third, each business's future: the line you will someday sell, or where a partner will come in, is best kept as an independent company with its own accounting and history — selling a division "smeared" inside a multipurpose company is a guaranteed discount on the price.

The corollary matters: within the same legal entity, one line's profits absorb another's losses automatically. Between separate companies, they don't — tax consolidation disappeared in 2014 and the optional regime for groups (arts. 59 to 71 LISR) is a partial deferral with requirements that few mid-sized groups justify. If one of your lines is going to lose money for several years, keeping it separate means those losses wait their turn on their own. That, too, is design.

Cross-financing: where the structure actually pays off

The efficiency almost everyone senses but few land is this: you have a consolidated company generating steady cash flow and a new project that needs capital. Without structure, the typical path is fiscally expensive — the consolidated company distributes dividends to you (with its additional 10% ISR on you as an individual), and you personally inject capital into the project. With structure, the surplus travels directly from company to company as an intercompany loan or as capital, without passing through your pocket or triggering the distribution tax. And if there is a holding company on top, dividends among group companies flow with no additional corporate ISR via CUFIN (the after-tax profits account) — the full peso works in the startup, not the peso minus tax.

The conditions aren't decorative: a loan agreement with a verifiable date (fecha cierta), interest agreed at market value — since 2022 the transfer-pricing obligation applies to all related parties, domestic ones included (arts. 76-XII and 179 LISR) — a payment schedule and real payments. The intercompany loan that is renewed for decades without being amortized stops looking like a loan, and the SAT has presumptions ready to recharacterize it — the full detail is in loans that are never repaid.

Where the line is (and the labels for each zone)

Safe: separating by risk, by VAT profile or by intent to sell, with real operations in each entity — the business reason is evident and precedes the tax benefit. Defensible: intercompany financing documented at market and deducting each expense in the entity that genuinely consumes it; it demands paperwork discipline, but the standard is attainable. Risky: re-invoicing services among your companies (administrative "fees", brand royalties) with no demonstrable substance or supported prices — it's a deduction in one, income in another, and materiality you will have to prove. Red zone: fragmenting yourself to reach capped regimes — the RESICO regime for legal entities blocks this at the source: companies whose partners hold a controlling interest in other companies cannot be taxed there (art. 206 LISR) — or moving profits among entities solely to erase tax, which is exactly the scenario art. 5-A CFF allows to be recharacterized. The rule of thumb: if the only answer to "why does this company exist?" is "to pay less", the structure isn't ready.