It’s a call or letter that no owner of an American Express credit card wants to receive: a notice that American Express is putting your account under financial review.

Scan the Internet and you’ll find countless stories of cardholders who struggled to work with American Express, only to have their accounts closed after this financial review. What infuriates people most is that there seems to be no logical pattern for what triggers an American Express financial review.

Here’s the basics, though: When you sign up for an American Express card, you give your agreement that the company can conduct a financial review of your account at any time. You also agree that American Express can cancel your card for any reason that the company chooses.

Some say that unusually large purchases, or an uncharacteristically busy period with lots of charges, will trigger an American Express financial review. American Express, though, isn’t sharing trigger points with the general public.

What usually happens with such a financial review is that cardholders receive either a letter or a phone call telling them that their accounts are under review. During the review time — which can last several months — American Express will deactivate these consumers’ cards.

American Express will then ask for a series of financial documents, usually cardholders’ most recent federal income tax returns and their bank statements from the last three months. If cardholders don’t provide this information, American Express will close their accounts.

Many cardholders view this as an invasion of privacy. Why, they ask, are their bank statements and income-tax returns any business of American Express’? This is a legitimate point. But it’s also a moot one: Cardholders aren’t about to change American Express’ policies.

Cardholders, then, who come under financial review have two choices for how to deal with this intrusion: They can quickly gather their documents and send them, by fax, e-mail or regular mail, to American Express, or they can refuse to do so and walk away from their accounts.

It all depends upon how committed to their American Express cards consumers are. Some cardholders can imagine using any other type of card. Others are happy with any card that provides a similar interest rate and benefits.

Cardholders should consider where they fit before they decide how to react to an American Express financial review. If they’re able to find another card that provides the same or better benefits, then there’s little reason to go through what everyone agrees is a hassle-filled procedure from American Express.

Those who truly enjoy their American Express cards, though, have little choice but to participate in any way they can with American Express’ financial review procedures. Yes, it is a cumbersome and invasive process. But those cardholders who want to maintain their relationship with American Express have little choice but to comply.