- Letters and envelopes designed to look like government correspondence, saying you need to renew your business registration for $200. The actual requirement (annual statement of information) is about $20, and can be done online. These scam artists trick business owners who don't know into thinking it's $200 (effectively $20 for the filing, $180 for their "service"). My dad (a family practice doctor) didn't learn this until after he retired, and he found one of these letters in my trash and demanded to know why I was throwing out a government notice. By our estimate he paid over $5000 to these crooks during his career. These got so bad that many states passed laws requiring any correspondence for a service assisting with filing government forms have "THIS IS NOT A GOVERNMENT NOTICE" printed all over.
- Letters masquerading as subscription renewals for things you haven't actually subscribed to. They're hoping someone in accounting doesn't know you haven't actually subscribed to it, assume it's a renewal so they won't investigate it to see if it's legit, and just pay it.
- Package delivery fees for your clients. If you're in a business where your customers temporarily or permanently share your address (hotel, landlord, etc), sometimes your customers don't pay their bills to other companies. These companies then try to trick you into paying the bill because you share the same address. They'll send you a legit invoice with your company name as the purchaser/recipient. Buried down in the handwritten description of the charge it'll mention your client who is the actual payer.
- A company who sold merchandise to one of our customers tried to pull this on us too. They said that was the billing info the customer gave them. I give them the benefit of the doubt - I assume it was a mixup between billing address and shipping address.
- Information harvesting. These aren't a direct financial attack. I think they're just collecting marketing info so they can sell it. The most memorable one I got was by phone. They claimed to be from the DMV and asked some basic information about our company (size, revenue). Some of our vehicles are registered with the DMV for off-road-only use (i.e. on our property only) so it's not unusual for us to get a call from the DMV about this. But when they started asking about our payroll info, the alarm bells went off. I asked why the DMV needed that info, and they hung up. Thinking back, I think they actually said they were calling from the "DNV" not the "DMV".
- These can come by mail too. I've gotten one designed to look like the Bureau of Labor Statistics forms our company was sometimes randomly chosen to fill out. Only difference was the destination fax number. I only noticed it because while I was prepping the report, I noticed I had already sent the report for that month. That's when I dug into it a little more and discovered the fax number was different.
- Designed to look like another bill. I've gotten two of these - one mimicking a utility bill, one saying I had to pay something for my Google account. The Google one was an obvious fake. The one mimicking my electric bill was really good. If I had been paying it by hand, it might have slipped through. I caught it because according to my accounting program, I had already paid the electric bill that month. I think they were counting on people making the payment check out to "SCE" instead of "Southern California Edison", and mailing it in that handily provided return envelope with pre-printed address.
- Standard fake IRS notices, telling you to call a phone number to pay. The phone number goes to the scammer, not the IRS.
Taken individually, these attacks are usually pretty easy to spot. But when you're hit with so many of them over the years, even if you catch 99% of them, a few will slip through.