Friday, 4:40 PM. Twelve envelopes in the mailbox out front, flag up. Supplier, fuel card, the guy who fixed the mower deck. Done for the week.
Here's a hypothetical, and everyone in it is made up. Tess runs Copperline Landscape Supply (a made-up business) with three trucks and an MCA debit of $212 every weekday. She still pays most vendors by check, because half of them are small family shops that ask for checks.
Last month she read about check washing, so she bought a pack of gel pens. Permanent black ink. Washing problem solved.
Monday, 9:15 AM, the bank calls. Two checks hit her account over the weekend: $6,480 and $3,925. Those are the exact amounts of the two biggest checks she mailed Friday. The amounts are right. The payee names are not. Neither one is her supplier.
Here's the turn. Nobody washed anything. The gel ink did its job. The thieves didn't need to change her handwriting. Every check she mails carries her business name, her address, her routing number and her account number. That's everything you need to print a brand-new check that looks like hers.
That's not a made-up twist. It's the real case this composite is based on. In October 2026, a Lancaster County, Pennsylvania excavation business had 12 outgoing checks stolen from its own mailbox, and it was caught on its surveillance video. Within 24 hours the bank called about two fraudulent checks for more than $21,000. They matched the amounts of the two largest checks mailed the day before, with new payee names and memo lines (WGAL).
The post office isn't automatically safe either. On October 22, 2026, a Baltimore-area TV station reported checks that went missing after people mailed them from inside a post office. One batch of 25 checks totaled about $5,600, and three later resurfaced rewritten for more than $35,000. An American Bankers Association fraud executive told the station that gel pens are recommended but won't stop all check fraud, because thieves can use your account and routing numbers to create another check (WMAR-2 News).
Business checks are the prize. FinCEN warned banks that business checks "may be more valuable because business accounts are often well-funded and it may take longer for the victim to notice the fraud" (FinCEN alert FIN-2023-Alert003). Thieves hit blue collection boxes, unsecured mailboxes and cluster boxes, then wash, copy or counterfeit the checks and move the money fast.
For an owner with a daily MCA debit, the math gets ugly quick. If $10,405 leaves the account over a weekend, Tuesday's $212 debit can bounce while you're still on hold with the bank.
Red flags
A vendor says your check never arrived, but your bank shows it cashed. The USPIS says that can mean you're a victim of check washing (USPIS).
A check clears for the right amount but to a payee you don't recognize. Thieves don't always change the dollar amount, so a quick balance glance can miss it.
A cleared check that looks different from your own check stock, or shows faded handwriting under darker writing. FinCEN lists both as red flags (FinCEN).
Cleared checks you never wrote at all. Thieves can counterfeit checks from the routing and account numbers on a real one.
Outgoing checks sitting in a mailbox with the flag up, especially overnight. The flag tells the carrier there's mail. It tells everyone else too.
A collection box that looks stuffed full. In one 2026 California case, police said thieves stuffed post office drop boxes with cardboard so new mail piled up where they could pull it back out (Ventura County Sheriff via edhat).
What to do
Stop mailing checks from your own mailbox. If you must mail one, the ABA's Practice Safe Checks site says to take it directly to the post office and send it Priority Mail, use permanent gel ink, and keep memo lines vague (Practice Safe Checks).
Move big vendor payments to electronic payments where you can, and ask the vendor to confirm bank details by calling a number you already have.
Ask your bank about Positive Pay. You send the bank a list of the checks you issued, and it flags checks presented for payment that you didn't issue (OCC check fraud guide).
Check cleared checks, not just the balance. Look at the payee line on the check images in your banking app every few days.
If it already happened, call your bank right away and check your deposit agreement for reporting deadlines. Report mail theft to the U.S. Postal Inspection Service at uspis.gov/report or 1-877-876-2455, then file a report with local police. Tell your MCA funder before the next debit bounces, not after.
More scams hitting owners right now are in the Scam Report.
Tess still buys the gel pens. Now the box of 500 envelopes rides in the truck, and the mailbox flag stays down.
