We have a single member LLC that applied for an EIN. For an example, the name on the account is ABC d/b/a XYZ.

What type of document would we get to verify the business? Also, we would get beneficial ownership, correct?

What you need to verify that the business is properly registered in your State is a State law issue. Applying for an EIN is an IRS issue and not related. A DBA usually reflects the fact that someone or some entity is operating under an assumed name.

And beneficial ownership?

An LLC is an entity. You have to get a beneficial ownership certification.

The confusing thing about a single member LLC is that for tax reasons, it can be treated like a sole proprietorship. However, don't confuse tax rules with CIP/BSA rules. While a single member LLC is taxed differently than other corporations, it is still a separate legal entity. Therefore, you need to verify a single member LLC just like you would for any other entity. Depending on your CIP policy, this often includes getting articles of incorporation/existence from your Secretary of State and any other documents your CIP requires. As John said, single member LLCs absolutely need the beneficial ownership designation as an LLC is an entity. Again, my point is that IRS rules (and how single member LLCs are taxed) are a completely separate issue from CIP/BSA rules, as CIP (generally) treats a single member LLC just like any other entity.