The battle for privacy begins. (Test Inform Protect).

The balance in your checking account. Your income. The amount of equity you have in your home. The size of your car loan. How much wine and alcohol you bought with credit cards. You wouldn't dream of revealing such information to anyone but your immediate family. What you may not realize, however, is that financial institutions have the power to share that information with other companies, almost without limitation.

The Gramm-Leach-Bliley Act is largely responsible for making your financial life an open book. Passed by Congress in 1999, it allows banks, insurance companies, and brokerage houses to sell one another's products and services. The business affiliations that the law enabled also allow those institutions to share sensitive consumer financial information. As a result, data previously held by a single company are readily available to its affiliates as well as to third parties who enter joint marketing agreements.

Consumer-privacy protections are minimal. A company must give customers a written explanation of its privacy policies. And the company, in some instances, must allow customers to elect not to have their information shared with unaffiliated third parties.

Shared information may include bank-account balances, loan-payment history, and credit-card charges, which could itemize your liquor and pharmacy bins. Such data may enable a financial institution to create a detailed customer profile, which has you paying a higher rate of interest for a loan--or not getting one at all--because the bank decided you used too many drugs or drank heavily.

The federal law, while weak itself, invited states to enact stronger consumer-privacy protections. North Dakota voters have already approved a strong financial-privacy law. And California is considering a bill that would require consumers to give permission before financial institutions could share ...