Both American and European authorities are angry about Irish rules that let firms pay as 12.5 percent taxes, or nearly a third the U.S. rate. Some officials think it may qualify as illegal state aid.
Here's a fact that might surprise you: All of the top 10 U.S. companies that were born on the Internet - including Google, Amazon and eBay - have overseas corporate headquarters in Ireland. The American tech sector is huge in Ireland. It's growing rapidly - and having a huge impact on life there.