You get privacy notices in the mail — tucked away inside statements from your bank, credit union, insurance company, stockbroker, mortgage lender, etc. — but chances are you don’t pay any attention to them.

Well, you should. These institutions have a lot of information about you (your Social Security number, for example) — and under the federal financial modernization law which took effect July 1, 2002, they have to tell you what they do with that personal data.

You can’t stop them from sharing it with their subsidiaries or affiliates, but if they want to sell it to a third party — a practice that some consumer advocates say increases the risk of identity theft — they have to give you a chance to “opt out” (say “no).

So … how do you do it?

1. Take the time to read the fine print. Most privacy notices offer a toll-free number or form that allows you to block the sale of your information to another company. (You can get replacements for any you’ve thrown away by contacting the individual institutions.)

2. You can also draft your own “opt-out” notice. A sample is available online at http://www.privacyrightsnow.com.

3. The law requires financial institutions to issue privacy notices every year.

But, watch the mail. You’ll get additional privacy notices when you open a new account or when a company changes its policy.