Seniors are often regarded as our nation's most vulnerable population, largely due to health and mobility issues that often leave them isolated. Seniors also tend to financially insecure -- particularly those who rely mostly on Social Security to pay their bills. It's not surprising, then, to learn that 27% of retirees are concerned about falling victim to financial fraud or a money-related scam, according to a new survey by the Society of Actuaries. If you share similar fears, here are some important rules to keep in mind.

1. Guard your Social Security number

Your Social Security number is an important identifier. Once a criminal gets hold of it, he or she can use it to open a credit card in your name or even attempt to steal your tax refund or Social Security benefits. That's why you should never give your Social Security number out without first fully vetting the person, company, or agency that's asking for it. And also, don't carry your Social Security card with you. There's really no need for that, and if your wallet is lost or stolen, you could end up with a serious identity theft problem on your hands.

Older woman with serious expression resting head on fist


2. Don't give out your Medicare ID number

A criminal may not be able to use your Medicare ID number to open a bank account, but you never know what trouble someone unscrupulous will cause. While it's OK to provide your medical providers with that information, don't give it out to people calling randomly over the phone asking you to verify your benefits. That's not something Medicare itself does, and while a medical office may need to do it, make sure you're actually talking to that office before sharing those details -- namely, by hanging up and initiating a call to that office yourself.

3. Safely discard all documents containing personal information

You probably get your share of financial statements in the mail containing information criminals can use to their advantage. To avoid dangerous consequences, invest in a paper shredder and make a point to shred any documents containing your Social Security number or account information.

4. Don't keep your banking or credit card passwords written down and posted in your home

Difficult as it may be to remember your various banking and credit card passwords, writing them down and posting them in different corners of your home is a bad idea. Chances are, you'll forget they're there, which means any time you have a repair professional, cleaning service, or delivery person enter your home, that individual will have an opportunity to access those passwords -- and that's a recipe for disaster. If you need help remembering your passwords, try using a password manager on your computer. And while emailing them to yourself isn't a great idea, it's safer than writing them down and storing them in plain sight.

Financial fraud is a scary thing, and unfortunately, seniors are particularly vulnerable to it. If you're worried about being a scam victim, stick to the above rules. Doing so could spare you a world of stress and heartache.