Apple says it is at risk of being hit with a higher tax rate and back taxes as European regulators investigate its tax affairs in Ireland.

In June, the European Commission launched a probe to see whether Apple's 1991 tax deal with Ireland violated European Union laws prohibiting state aid to companies. Ireland and Apple say they work in accordance with the law.

In the company's annual financial report, released this week, Apple warned investors that "If the Company's effective tax rates were to increase, particularly in the U.S. or Ireland...the company's operating results, cash flows and financial condition could be adversely affected."

Related: How Apple socres its lower tax bill

Apple (AAPL, Tech30) has paid as little as 2% on profits attributed to its subsidiaries in Ireland, well below the 35% top rate in the United States and even well below Ireland's 12.5% rate. That has prompted complaints by both European and U.S. lawmakers. CEO Tim Cook was even called to testify on Apple's tax deal before a Senate committee.

To soothe angry regulators, Ireland announced earlier this month that it would end a key tax loophole for tech companies by 2020.

But some experts say the change is more of a public relations move than a step that will significantly increase the taxes those companies have to pay.

蘋果公司表示，它可能會失去愛爾蘭減稅
由克里斯·伊西多爾 @CNNTech 2014年10月31日：9:15 AM ET

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蘋果公司說，在被打了一個更高的稅率和稅款風險 歐洲監管機構調查的稅務愛爾蘭。
在6月，歐洲委員會展開了調查，看看蘋果1991年能否稅務處理愛爾蘭違反了歐盟法律禁止政府援助的公司。愛爾蘭和蘋果公司說，他們在依法工作。

在該公司的年度財務​​報告，本週公佈，蘋果公司警告投資者，“如果公司的有效稅率分別為增加，尤其是在美國還是愛爾蘭...公司的經營成果，現金流量和財務狀況可能會受到不利影響。 “
相關報導：蘋果如何socres其較低的稅單
蘋果 （AAPL，Tech30）已支付低至2％的歸因於它在愛爾蘭子公司利潤，遠低於頂率在美國35％，甚至低於愛爾蘭的12.5％以上。這促使了歐洲和美國國會議員的投訴。公司首席執行官蒂姆·庫克甚至被稱為前參議院的一個委員會作證蘋果的稅務處理。
為了安撫憤怒的監管機構，愛爾蘭本月早些時候宣布，將結束一個重要的稅收漏洞的高科技公司到2020年。
但一些專家說，變化更多的是一種公共關係不是一步，這將顯著增加，這些公司必須支付的稅款移動。