Under tax equalization you keep paying roughly what you would have paid at home, and the employer covers the difference either way — so a low-tax posting benefits the employer, not you. Under tax protection you pay the lower of the two, so you keep the upside. Both remove downside risk; only one lets you gain from where you are sent.
Equalization, in one paragraph
A hypothetical tax is calculated — what you would have paid had you stayed home — and deducted from your pay. The employer then settles your actual liabilities in both countries. If the host country taxes more, the employer absorbs it. If it taxes less, the employer keeps the saving.
The logic is that nobody should accept or refuse a posting because of its tax rate, and that the company should be neutral about where it sends people. It is common, it is defensible, and it means a posting to a low-tax jurisdiction does not enrich you.
Protection, in one paragraph
You pay the lower of your home liability and your actual liability. The employer covers any excess above the home figure and lets you keep any saving below it. Better for you and more expensive for them, which is why it is less common.
Why the distinction is worth a question
Because the words are used loosely and the difference is real money. “We’ll take care of the tax” is compatible with both. Ask which one, in writing.
The hypothetical tax is the thing to check
Under equalization your entire deduction depends on an assumption about a return you never filed — which state is treated as home, what filing status, what other income is included. Those assumptions are set by the employer’s tax provider and they are negotiable inputs rather than facts.
What both arrangements usually cover, and do not
They normally cover employment income and employer-provided items. They frequently exclude investment income, rental income and spouse’s income. And they end — assignments produce trailing liabilities into later years, so establish who handles filings after you come home and for how long.
The practical questions
Equalization or protection. Who prepares the returns and who pays for it. What income is inside and outside the arrangement. And how long the support continues after the assignment ends.
Common questions
What is tax equalization?
A hypothetical home-country tax is deducted from your pay and the employer settles your real liabilities. You end up roughly tax-neutral wherever you are posted.
How is tax protection different?
You pay the lower of your home liability and your actual liability, so you keep the benefit of a low-tax posting. It is better for you and less common.
Why does the difference matter?
Because under equalization a low-tax posting benefits the employer rather than you, and both are often described simply as taking care of the tax.
What is the hypothetical tax?
An estimate of what you would have paid at home. Its assumptions — home state, filing status, what income counts — are set by the employer's provider and are negotiable.
Does it cover all my income?
Usually employment income only. Investment income, rental income and a spouse's income are frequently outside the arrangement.