If we deny a claim can we tell the customer that they have only ten days to request copies of the documents used during the investigation?

Although there's nothing in the regulation that says you have to make the documents available for ever, there's no provision for restricting the time, either. I suspect that the framers of the regulation envisioned a file into which you would put all your paperwork, and they didn't think about limiting access to it after the fact.

If you do decide to push the envelope here, I recommend more time than 10 days. It could well be that the customer doesn't get your notice until almost the end of that time.

I agree with John. 10 days is not reasonable for this. Since these documents should be held for audit review anyway, I wouldn't see any reason to destroy them before that is done. My own estimate would be a minimum of 90 days. If you audit less frequently, save them for at least that time. Similarly, your examiners will want to see these files when they audit you. And if the consumer wants to complain about this, that takes a month or two.

So, while files may not be needed for review by the customer, others may want to review these to ensure compliancy.

Since the retention requirements for Reg E is two-years (205.13(b), I would recommend that you don't destroy any documents relating to a Reg E claim for at least that long. Since the retention period is specified in the regulation, I would be hesitant to tell the customer that yes, we are required to maintain the records of your claim investigation, but no, you can't see them.

I'm in total agreement on this. Since 2 years is the retention requirement, and since the customer has the right to see the documents used in deciding the claim, I'd say the customer has a right to see the docs for 2 years.