I'm hoping someone here has seen this before.
When I pull my April 2026 sales tax report, I see three line items under Tax Name: MA, Massachusetts, and Mo. I've been able to account for the first two — MA is in-person sales tax collected at the register, and Massachusetts is the automatic destination-based tax on online orders via Square's Tax Enrollment. But I cannot figure out where Mo is coming from.
Here's what I've already ruled out:
- I have no Missouri transactions in April. I've exported my full April transactions CSV and checked every row.
- I have only one manually configured tax (MA, 6.25%). There is no "Mo" tax in my Sales Taxes settings.
- My Tax Enrollment shows Massachusetts only.
I contacted Square support today and was transferred six times without a resolution. One agent suggested it was Missouri destination-based tax on a shipped order, but I don't ship to Missouri and the transaction data confirms this.
Has anyone seen a "Mo" line item before? Any idea what generates it or how to make sense of it for tax filing purposes?
