The IRS' contact information is displayed on the CP2000 notice in the top right corner of the letter: Phone number: 1-800-829-8310. Fax: 1-877-477-9602.
An IRS principal business code is a six-digit number that the IRS usually assigns to your business based on the revenue and activities you report in your tax filings.
Since its establishment, the IRS has been largely responsible for collecting the revenue needed to fund the United States federal government, with the rest being funded either through the U.S. Customs and Border Protection (collecting duties and tariffs) or the Federal Reserve (purchasing U.S. treasuries).
If your address has changed, please call 1-800-829-8374 or visit .irs . Please check here if you've included any correspondence. Write your Social Security number , the tax year (2011), and the form number (5329) on any correspondence.
267-941-1000 for international callers or overseas taxpayers. (Overseas taxpayers may also fax a tax question to 681-247-3101 or use our international contact address page.)