Letter 135C: Power of attorney needed: the IRS will not answer the person who wrote

What Letter 135C is

"Power of Attorney Needed to Furnish Information." Sent to an unauthorized third party who wrote asking for a reply, with a separate letter to the taxpayer explaining why (IRM 21.3.3.4.16.4(10), Oct. 1, 2025). Before writing, AM checks the CAF and RAF; only a representative on file, or an authorized reporting agent, receives copies. The business exception: "For BMF taxpayers only - If the correspondence from the unauthorized third party is on the corporate or sole proprietor's letterhead and the address matches the address of record, do not send a Letter 135C."

The deadline

No deadline. The underlying inquiry is not being worked for the writer until authority is on file.

What to do

Have the business itself reply on company letterhead from the IRS address of record, signed with name and title, or file Form 2848 or 8821 for the person who wrote. An original 2848 or 8821 enclosed with correspondence is accepted if complete and forwarded to the CAF unit (IRM 21.3.3.4.16.4(9)).

Who the IRS will write to

The IRS may disclose a taxpayer's return information only to the taxpayer or to someone the taxpayer has authorized, and the authorization has to be on file in a form the IRS recognizes. For businesses that means a Form 2848 power of attorney (which lets the representative speak and sign for the taxpayer), a Form 8821 tax information authorization (which lets the IRS share information with the person but not take their instructions), or a Form 8655 reporting agent authorization limited to the employment and withholding tax accounts it names. When a letter arrives from someone who is none of those, such as an outside accountant who has not filed a 2848, a vendor's compliance consultant, or a new finance hire writing from a personal email domain, the IRS does not answer the question. It sends Letter 135C to the writer saying authority is needed, and a separate letter to the business explaining that someone wrote on its behalf. The business exception is narrow: a letter on the company's own letterhead from its address of record is treated as the company's, even if the signer is not on file.

Getting the inquiry worked

The quickest fix is for the business to write again itself, on letterhead, from the address of record, signed by an officer with name and title, restating the question and attaching the 135C. If an outside representative needs to handle the matter, have the business sign a Form 2848 (to let them act) or a Form 8821 (to let them receive information) and enclose the original with the next letter; a complete form enclosed with correspondence is accepted and forwarded to the authorization file, though it adds processing time, so filing it online in advance is faster. Note that a Form 8821 holder cannot sign a penalty abatement request or an appeal; for those, a 2848 is required. Until authority is on file the underlying question sits unanswered and any clock on it keeps running, so do not wait for the IRS to prompt again. The correspondence guide covers how the campus screens incoming mail, and the Letter 147C page covers the most common request an unauthorized person makes, since a 147C is released only to someone with authority over the EIN.

Questions about Letter 135C

Have a different notice? The IRS notice decoder lists all 77 in the order they tend to arrive.