If you've changed your business name, you'll want to inform the IRS so that your Employer Identification Number (EIN) can be transferred over to your new business name. EINs can't change hands when you sell your business or if you've made significant structural changes to your business like taking on a new partner. Sole proprietors, corporate entities, and partnerships who have only changed business names are eligible to transfer the EIN to the new business name.
Check out the IRS "Do You Need a New Name Change?" website to see if you are eligible to transfer your EIN.
Write a letter (on company letterhead if possible) informing the IRS of the name change. Include the business name (both old and new), the EIN, and your mailing address.
Sign the letter. If you are a sole proprietorship, the business owner should sign. For a corporation, a corporate officer should sign. For a partnership, one of the partners should sign the letter.
Mail the letter to the IRS at the address you you sent your tax return to last year.