As many of us know, Apple has been hoarding massive sums of cash in Ireland where it has a very friendly tax deal in place. This is a practice that landed Tim Cook in front of the US Senate last year and since sparked proposals by Ireland's Department of Finance that could shut down the tax haven for good.

The move by the Finance Department was initially part of its continued cooperation with the European Union to clean up corporate tax issues, and now the EU is set to start its own investigation into the way nations like Ireland allow massive multinationals to receive such lofty tax breaks.

Apple's Ireland holdings, Starbucks in the Netherlands and Fiat Finance and Trade in Luxembourg are among the corporations and tax deals being looked at. The investigation is being led by Joaquín Almunia, the European Union's competition commissioner and could very well leave Apple and other country's cozy tax deals in the dust if it were to lead to changes.

Ireland has been a country of choice for many large tech companies. Apple is said to have as much as $100 billion stashed there. On top of the already low (12.5%) tax rate, Apple and other multinational companies also get further tax breaks and benefits from the Irish government.

On top of the obvious issues this could present for Apple and Starbucks, Ireland has used its friendly tax arrangement to attract major companies like Apple to headquarter there. This in turn creates jobs for Irish people and builds a certain level of reputation for the country that it wouldn't have otherwise.