We file a SAR on a customer for structuring in their personal account (initial SAR). After the SAR is filed, a month later, customer starts structuring in their business account. Wait for the supplemental review and check off continuing on the SAR or is this an initial because customer is structuring in a different account? Thoughts?

This is my opinion only -- individuals structure transactions; businesses don't. Your said that the business is owned by the individual, right? I'd broaden my ongoing review scope to include both accounts (and any other accounts owned by the individual or the individual's businesses) and wrap the whole thing into the next continuing SAR for the individual, adding information on the other accounts he/she appears to have been using for structuring.

I second John's suggestion. There is no need to file separate SARs if both accounts have common ownership. Wait for the supplemental review period and pack them together.

I absolutely agree with John; people do it businesses do not.