A TDI usually begins as a result of the I.R.S.’ computerized return matching program, known as the Information Return Processing (IRP) program. This program matches all incoming information returns (such as W-2s, 1099s, etc.) against filed tax returns (1040s, etc.).

When the program finds an information return for which no tax return has been filed, it generates a transaction code 140 to the IMF (Individual Master File). This begins the TDI stage of the I.R.S. investigation, which is generally recognized by the I.R.S. sending between one and four requests for returns. These requests are usually in this order, but the interim reminder requests CP-516 and CP-517 are rarely sent:

1. Notice CP-515, “REQUEST FOR TAX RETURN”

2. Notice CP-516

3. Notice CP-517

4. Notice CP-518, “YOUR TAX RETURN IS OVERDUE”

Sometimes, this initial request for a tax return is accomplished by a letter

from an I.R.S. agent, not computer generated like those above.

Responses used for these:

TDI 1 (Response to a CP 515 or other initial request for tax return)

The Enclosures mentioned in this letter are included in the same folder.

TDI 2 (Response to a CP 516, 517 or 518)

TDI 3 and

TDI 4 are more of the same types of letters.

Other responses which might have been made at this stage

(each must be read to understand what they address) are in the

TDI - request for returns phase

I.R.S. letter responses available (also see Miscellaneous below):

In addition, I.R.S. officers may personally request attendance at a meeting to discuss un-filed tax returns. Sometimes, they directly request information that they plan to use to prepare a return for you under IRC 6020(a). Responses used in the past include this meeting letter.

Other TDI Phase response letters Are Available Here!.

OR, Check the Master List of Documents!