When assigning NAICS codes for Holding companies, should a 551 for Management of Companies and Enterprises be used or should the code for whatever the Holding Company is (they buy Real Estate, so they basically are investors of Real Estate) be used, like 531?

Might depend on what you are using the NAICS code for. But if all they do is hold the stock of other companies and potentially provide management direction to other companies, that would be correct.

It would ultimately be used for CTR purposes. Cash in and out, which is where I'm wondering if the more detailed description is what we want?

Well, I am having a hard time justifying why a true holding company would be dealing in cash deposits and withdrawals of that size. In addition to deciding on the NAICS code, you might want to consider doing a little more digging to figure out just what this "holding" company is doing.

Exactly...… holding company says "investment company" but all of the accounts associated are "real estate". More digging to come but noticed the NAICS code right off and made me question. I think it is "training" on finding out what the company REALLY does...…. New to this bank!