Banks and mortgage companies usually want to profit from what they know about you, your family and your finances.

The marketing companies that buy the information will use it to peddle everything from insurance to siding, subjecting you to endless phone calls, junk mail and spam.

Of course mortgage applications are protected by the federal Gramm-Leach-Bliley Act, better known as the Consumer Privacy Act.

That makes it illegal for lenders to sell anything from that paperwork without your written permission. Unfortunately, they're very good at getting that.

A consent form is part of almost every mortgage application packet.

Anna DeSimone, a financial industry consultant and president of Virginia-based Bankers Advisory Service, says there's no standard design or wording for those forms. But they all provide the choice to opt "in" or opt "out" of their information sharing program.

"Always opt out," DeSimone says.

If you check the box to opt in you're granting the lender permission to sell your personal information.

Click here for more advice on how to navigate the mortgage application process.