Inbox Zero: Notice Season

Mail pours into your compliance desk tray from January to December, and every piece has one right move and a deadline ticking down. Sort fast, build combos and keep the penalty meter at zero while the seasons speed up.

You will learn what to do with each IRS notice and W-9, and how fastPrivacy runs in your browser; scores stay on your device

How to play

Press Start sorting. Mail drops into your inbox tray: W-9s, IRS notices, returned envelopes, emails, invoices and reminders.
Read the open letter, then send it to the right bin: click or tap the bin, press its number key (1 to 8), or drag the letter onto it. Arrow keys or a tap on the tray switch letters.
Every piece has a clock. Real deadlines (15 business days for a B-Notice, 45 days for a 972CG, a payment run) tick in business or calendar days; other mail only has tray time. Handle the most urgent first.
Right answers score 100 points plus a speed bonus, multiplied by your streak combo (up to x3). Wrong or missed items cost points and add real penalty dollars. A season with no mistakes earns a 250 point bonus.
Three seasons: the January rush (4 bins), spring CP2100 season (3 more bins) and the fall run with Notice 972CG (all 8 bins). Press P to pause.

The real rules behind the game

The game turns a year at a payer's compliance desk into single moves. Each answer follows this site's guides, which follow IRS Publications 1281 and 1586 and the Internal Revenue Manual.

Request a W-9. Ask for the TIN when a vendor relationship starts, before the first payment. If the TIN is still missing, the first annual solicitation is due by December 31 of the year the account opened, and the second by December 31 of the next year; no annual request is needed for a year with no payments. Re-solicit when a vendor's name, entity type or TIN changes. Annual requests go by mail or phone, not email. See W-9 solicitation rules.

Backup withhold 24%. Withhold from the first reportable payment when a payee has no TIN (a number that is not exactly nine digits counts as none), and no later than 30 business days after a CP2100 date when the payee has not returned a valid W-9 (first notice) or agency proof (second notice). The 60-day "applied for" grace covers only interest, dividends and certain readily tradeable instruments. See the backup withholding guide. A CP543 C-Notice (interest and dividend payers only) means withholding begins within 30 business days and runs until the IRS sends CP544 or Letter 2027-C; see the C-Notice guide.

First and Second B-Notice. For each CP2100 or CP2100A line that still needs correction, mail a First B-Notice with a W-9 within 15 business days of the notice date (or the date you received it, if later). If the same account appears again within three calendar years, send a Second B-Notice without a W-9: the payee proves the TIN with a Social Security card copy or IRS Letter 147C. A different name/TIN pair is a new first notice; a later notice for the same tax year's returns is disregarded. See the CP2100 guide and what the IRS manual says about CP2100s.

Fix our records, or file it. Do not send a B-Notice when the mismatch came from your own keying error, a correction you already made, or an IRS processing error. Do not write to the IRS about it, do not send it the W-9, and do not file a corrected 1099 just to change a TIN.

Stop withholding. Stop within 30 calendar days after a valid W-9 (first notice) or the SSA or IRS proof (second notice: an SSA card copy, Letter 147C, or Letter 685C for an ITIN) arrives. Amounts already deposited stay deposited; the payee claims the credit.

Answer the 972CG. You have 45 days from the notice date (60 outside the U.S.). For TIN failures, reasonable cause means proving the solicitations were made on schedule; First Time Abate does not apply, and a penalty on a timely filed return must be assessed within three years of its due date. See the 972CG guide.

Penalty dollars. The game charges the per-return amounts for returns due in 2027 under Rev. Proc. 2025-32: $60 if corrected within 30 days, $130 by August 1, and $340 after that or never; a TIN that is never corrected sits in the $340 tier. The IRC 6722 payee statement penalty is left out. Missed withholding is charged as 24% of the payment, the liability IRC 3406 puts on the payer. All figures are on the 2026 figures page.

What the game simplifies. Some situations need two moves at once (withholding on a no-TIN payee while you keep soliciting); the game asks for the most urgent one. Tray time on mail without a legal deadline is a game mechanic only. For a real notice, use the CP2100 decision tree and the B-Notice deadline calculator.

Sources

More knowledge games

Which Box?: A payment slides in, the clock runs: pick the right 1099 form and box before the timer bar empties.
Name Control Detective: Crack the four-character IRS name control on 16 case files before the clock runs out.
The Tip Shuffle: Deal tipped workers, then play the right occupation codes into the W-2 or 1099 box.
Penalty Drop: Drop late and wrong 1099s down a peg board, hit the $60 tier and call the right IRS rule to pay nothing.
Escape the Filing Room: Locked in the filing room on January 30: crack seven 1099 puzzles before the clock hits midnight.
Fifty-State Sort: Route each 1099 to CF/SF, a direct state filing or nothing at all, and fill in a map of 50 states and DC.
Treaty Passport: A foreign payee's passport lands on your desk: stamp the right withholding rate, 30% or the treaty rate.
The 1042-S Slot Machine: Spin and nudge the reels to the right 1042-S codes: income, chapter 3 and 4 exemptions, recipient status.
Form Inspector: Run the W-8 desk: hand each foreign payee the right form, then approve or reject the forms that come back.
Deadline Dash: Filings fly in and the clock runs: tap each one's 2027 due date on the calendar before time is up.
Real or Fake TIN?: Swipe SSNs, ITINs and EINs as valid or impossible, name the TIN type, then decode IRS TIN matching codes.
Match Code Rush: Vendor records roll in: predict the IRS TIN Matching code, then fix the record before it turns into a B-Notice.
Reject Rescue: IRIS acknowledgments land one by one. Read the status and rule codes, then make the right next move.
Get Your TCC: Roll the weeks and race the calendar from ID.me to an approved IRIS TCC before the 2027 due dates.
CSV Cleanup Crew: Turn a messy vendor export into an upload-ready IRIS portal CSV: map the headings, fix the bad cells, split the file.
Schema Surgeon: Operate on IRIS A2A transmissions: find the broken XML nodes, fix them, and get Accepted in ATS.
FIRE to IRIS: The Move: Sort FIRE-era filing habits into still true, changed or gone before the IRIS season starts.

Inbox Zero: Notice Season