Your CPA needs a closed set of books and the evidence behind each number, not a folder of platform exports. Concretely: a profit and loss statement and balance sheet through December 31 that tie to bank, card, and loan statements; a year-end inventory value backed by a count and a roll-forward; a bridge from each platform's Form 1099-K to booked sales; a roll-forward of every sales tax liability account; clearing accounts that explain themselves; and a short memo listing what you are unsure about. Everything below is the detail of that list, and the reason a CPA asks for each piece.
A CPA billing by the hour who receives raw settlement files will rebuild your books before preparing anything. That is the expensive way to file. Worse, a CPA working from a P&L with one line called "Amazon" cannot see that revenue includes marketplace facilitator tax, that fees are netted inside sales, or that inventory never got relieved for liquidated units. They will either ask, and wait, or make an estimate you will not like. The package below removes the guesswork.
A reconciliation report that shows a stubborn $1,812.40 "uncleared" from April is not a detail. It means some transaction posted twice or never posted, and the CPA cannot tell which.
Payment apps and marketplaces must furnish Form 1099-K by January 31, per the IRS page "Understanding your Form 1099-K." So the revenue section cannot close until February's first days. Prepare the books side in December so that when each form arrives you only drop in Box 1a and confirm the reconciling items. The method is in matching the 1099-K to your books.
For each channel, give the CPA gross sales, shipping income, discounts, refunds, each fee category, and net deposits, plus the bridge from the form to those figures.
This is where most ecommerce returns go sideways, and where CPAs spend the most questions.
A list of non-employee payees with totals, addresses, and W-9 status. IRS Publication 1099 for 2026 says the minimum threshold for reporting certain payments rose from $600 to $2,000 for tax years beginning after 2025. Which of your payees that affects is your CPA's call; your job is the list. Keep the W-9s in one folder; the CPA will ask for them.
A roll-forward of each sales tax payable account: tax collected, less refunds, less amounts remitted, equals the ending balance. Also a statement that marketplace facilitator tax nets to zero and sits outside revenue. The year-end check is laid out in reconciling what the marketplace collected.
One page. List anything you were not sure how to book: a lawsuit settlement, a large prepaid ad credit, a vendor dispute, a product recall, a state notice. A CPA who reads about an issue in January can plan for it. One who finds it in March charges for the surprise.
Illustrative numbers. Take a seller with three locations: a 3PL, FBA, and a small office stockroom.
Expected closing inventory: $412,000.00 plus $1,180,000.00 equals $1,592,000.00. Minus $1,095,400.00 equals $496,600.00.
The December counts, valued at FIFO layers, total $471,300.00. The books say $496,600.00. The gap is $25,300.00, and the CPA will want it explained before anything else.
Working through the year's records:
Check: $14,800.00 plus $6,900.00 plus $3,600.00 equals $25,300.00. The gap is fully assigned.
Each line needs its own correcting entry, dated in the year it happened, and the shrink figure goes in the memo. How the reimbursements and the shrink are treated for tax is the CPA's decision. Your job is to give them the three numbers and the support, not a single "inventory adjustment" for $25,300.00 in December.
Illustrative numbers. An Amazon settlement period closed December 29 and disbursed January 2 for $38,450.00. December 30 and 31 activity in the next, still-open settlement nets to $6,200.00. On December 31, the Amazon clearing account should hold exactly $44,650.00. If it holds $58,370.00, the extra $13,720.00 is an older settlement that never got matched to its deposit, or a deposit posted to the wrong account. Find which before handoff. A CPA who sees an unexplained clearing balance has to choose between reclassifying it to income or leaving it on the balance sheet, and neither is right without the detail.
Most of this package falls out of the ledger if settlements were posted at the transaction level all year. ConnectBooks reconciles the sales, fees, refunds, and reimbursements in marketplace settlements and syncs them to QuickBooks or Xero as summarized entries or item-level detail, runs FIFO COGS per SKU with landed cost allocated, and reports inventory value and aging by warehouse. The year-end P&L becomes a report you run, not a project you rebuild.
If you do not yet have a CPA who works with marketplace sellers, the ecommerce accountant directory lists firms that do. And if the books still need the full December treatment, start with the year-end accounting checklist and come back to this list when the counts are done.
What to deduct, how to treat the shrink, and what to file are questions for your CPA. Giving them a package they can trust is the part that belongs to you.
Running an e-commerce business comes with plenty of challenges, but ConnectBooks is here to make your life easier. With real-time insights, seamless integrations, and detailed tracking of your profitability and inventory, you can stay ahead of the game. Whether you’re selling on Amazon, Shopify, Walmart, TikTok or eBay, ConnectBooks helps you manage your finances with 100% accuracy and confidence, so you can focus on growing your business.
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