Occupying a single floor of a three-storey building in a suburban Dublin office park, Western Union's offices are notably modest for the international headquarters of the world's largest money transfer firm.
The set-up is typical of swathes of US companies using Ireland to cut their tax bill. A Reuters analysis of Irish and US filings shows that more than 40 per cent of the S&P 500 have registered subsidiaries in the country.
That nexus, which has created over 100,000 jobs for Ireland, was laid bare when the US Senate revealed that technology giant Apple had paid little or no tax on tens of billions of dollars in profits channelled through the country.
Ireland, which has courted US business for decades, rejects the Senate's claims that it is a tax haven, but the case has damaged its reputation as it seeks to emerge from an EU-IMF bailout and its export-focused economy dips back into recession.
Company documents in Ireland and filings in the United States shows that many firms have multiple units in Ireland, where corporate income tax is 12.5 per cent - about a third of the top US federal income tax rate of 35 per cent.
In many cases, several subsidiaries are registered at the offices of Dublin-based law firms.
In Western Union's case, Unit 9, Richview Office Park houses 11 of its 12 Irish subsidiaries. The company made 92 per cent of its pre-tax income outside the United States last year, although a fifth of its staff work in the country.
That allowed the Colorado-based company to cut its effective tax rate to 12.2 per cent - about average for a large US company.
Companies, investors and some lawmakers argue it is a firm's duty to keep its tax bill as low as possible so it can invest to grow and return money to shareholders. Western Union said it pays full tax on all profits earned in Ireland.
"The (Irish) tax rate is not that relevant, because nobody pays 12.5 per cent," said Jim Stewart, a professor at Trinity College Dublin who specialises in corporate finance and taxation.
"It's about the ease of incorporation, the ability of Irish corporate law and tax law to fit in with IRS (Internal Revenue Service) requirements, and the flexibility that is shown by the Department of Finance and Revenue to any of the multinationals' needs. If they have a problem, the law will be changed."
A spokesman for Ireland's Department of Finance said it did not change laws to suit multinational companies and that its focus was on the local economy.
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