ACH vs wire for large B2B payments — which is safer?

Starting to get enterprise clients paying $20-50K invoices. They're asking for ACH or wire instead of credit card (makes sense, 3% fee would be brutal). Which is safer from my perspective as the vendor?

Wire transfers are essentially irrevocable once sent. ACH can technically be reversed within 2 business days (or longer for fraud claims). For large amounts where you trust the client, either works. For new relationships, wire is safer.

we do both. wire for first payment from new clients, ACH for ongoing if they're established. wire fees are $25-45 which is nothing on a $30K invoice

IMPORTANT: wire fraud is real. always verify wire instructions by phone using a number you already have (not one from the email). scammers intercept emails and change bank details. I've seen companies lose six figures this way

@FraudRisk yes, this happened to us as the payer. Our email was compromised, fraudster sent fake invoice with their bank details to our client. Client wired $45K to the wrong account. Took 6 months and lawyers to sort out who was liable. verify verify verify

Scary stories. How do you guys handle sharing bank details securely? Just send routing/account in a PDF invoice?

I put bank details on invoices but also include a note: "Please verify wire details by calling [phone] before sending large amounts." Some clients also use bill.com or similar platforms which handle the verification automatically.

Came across this thread while researching payment options for my agency. Super helpful advice here, especially @FraudRisk's warning about verifying wire instructions - I've heard too many horror stories.

Quick question though: has anyone used Mercury or similar fintech banks for receiving large B2B payments? My clients are used to traditional banks and I wonder if they'd be hesitant to wire to a "tech bank".

Actually in my expereince the fintech vs traditional bank thing is a non-issue. Most clients just care that the routing number and account number work. I've been using Relay for 2 years and never had a client balk at it.

@SmallBizSarah one tip: if you're worried about it, just don't mention the bank name. Your invoice just needs to say "Bank: [routing#] Account: [account#]" - nobody asks what bank it is.

Thanks for this thread - bookmarking for reference. We just landed our first $75K contract and I was panicking about payment logistics. Going with wire for the initial payment like @CFO_Startup suggested.

Also found the demand letter templates on this site which I'm hoping I never need but good to have in case payment ever becomes an issue with enterprise clients.