Similar to tech giants like and , major phone carriers track your personal data, and some use it to sell targeted ads. It’s the kind of practice most of us hurriedly agree to because, well, who has the time to read through the privacy policy of every service you sign up for? 

As it turns out, CNET does. Here’s what we found in all the fine print and what you can do about it.

Phone carriers like , and track various information, including your location, web activity, app usage and in some cases your credit. AT&T even collects users’ like fingerprints, according to its privacy policy — though only “until the initial purpose for collecting it has been satisfied or within three years of the individual’s last interaction with AT&T, whichever occurs first.”

Carriers use this information to improve customers’ experience, according to their privacy policies, and some sell this information to third parties. A lot of what is sold is information that you probably wouldn’t want your phone carrier selling. But you can stop your private data from being tracked and sold to third parties, and some carriers even offer ways to delete the data they have already collected on you. Not all data can be deleted, though, as each carrier states it keeps some of it for billing purposes and legal obligations.

Controlling what data of yours a carrier is tracking or has stored could protect you and your loved ones from a , which could compromise your bank account or ruin your credit. And with the proliferation of , including one at , the risk is real. So here’s how to have more control over your personal data, no matter what mobile carrier you use.

Important note: Even if you choose to not have your data sold, you’ll still receive ads. They just won’t be tailored to you and your interests, and some services might not work as well.

AT&T

Here’s how AT&T customers can stop the carrier from tracking their data:

1. Log into your AT&T account from a browser. 

2. Go to . 

3. At the bottom, there’s a section called Control How We Use Your Data. Click through each option and toggle On or Off for phone numbers on your account. Each phone number can opt in or out and it won’t have an effect on the other phone numbers on your account.

Customers who live in California and Nevada can tell AT&T to stop selling their data:

1. Fill out this form in a browser.

2. Click Do Not Sell My Data or Do Not Sell My Data Except to AT&T Companies at the bottom of the page.

AT&T says it shares “information in ways that may be considered a ‘sale’ of personal information” in California and Nevada, so that is why it only offers this option in those two states. 

AT&T customers in California can also . This doesn’t seem to be available to other AT&T customers, though.

T-Mobile

For T-Mobile customers, you can tell the carrier to stop tracking your data one of two ways. One is through the T-Mobile mobile app and the other is through your account:

1. Either open the T-Mobile app and sign in or log into your account from a browser.

2. Click My Account.

3. Click Profile.

4. Click Privacy and Notifications.

5. Click Advertising and Analytics.

6. Select your name (or the name of another user on your account) from the list.

7. Click the slider next to Use my data to make ads more relevant to me to turn it off. You can also click the slider next to Use my data for analytics and reporting to stop T-Mobile from using your data in marketing reports.

8. If you have multiple T-Mobile users on your account, click Back and repeat steps 6 and 7.

T-Mobile also lets its customers restrict the sale of their data to third parties through the Do Not Sell setting. Here’s how from a web browser:

1. Log into your T-Mobile account.

2. Open and scroll down to the section Learn more about the “Do Not Sell” setting.

3. Click Get Started.

4. Click which service you have — the options are T-Mobile, Sprint, Metro by Sprint and Assurance Wireless.

5. Under Do not sell my personal information, click the button on the right side of the screen to turn on the Do Not Sell feature. Click the button for as many items as you want to protect. 

T-Mobile customers can also fill out a form to . 

Verizon

Opting out of Verizon tracking customer data is a little confusing. Verizon has two advertising programs: . The main difference is Custom Experience Plus tracks a broader range of data, and you have to opt into the Custom Experience Plus program. Verizon customers are automatically signed up for the Custom Experience program, but they can opt out. While Verizon doesn’t sell customer data to third-party advertisers,  “de-identify or aggregate information so that Verizon or others may use it for business and marketing purposes.” 

Here’s how to tell Verizon to stop tracking your data in the Verizon Mobile app:

1. Open the Verizon Mobile app and log in to your account.

2. Click the Gear icon to open settings.

3. Under Preferences, click Manage privacy settings.

4. Choose the phone line whose privacy you want to manage.

5. Click Custom Experience to toggle Off for each phone number in your account.

6. Click Custom Experience Plus to toggle Off for each phone number in your account.

7. Click the back arrow at the top of the screen. Your settings should save automatically.

Here’s how to tell Verizon to stop tracking your data from a web browser:

1. Go to from any browser and log into your account.

2. Click Account.

3. Select Account Settings.

4. Click Privacy Settings.

5. Click Custom Experience and set to Don’t Use for each phone number in your account. 

6. Click Custom Experience Plus and set to Don’t Use for each phone number in your account.

7. Click Save Changes.

Deleting most of your data through Verizon is a little more hands-on, though. Here’s how to do it from mobile:

1. Open the Verizon Mobile app and log into your account.

2. Click the Gear icon to open settings.

3. Under Preferences, click Manage privacy settings.

4. Click Custom Experience Settings

5. Click Reset.

And here’s how to delete most data Verizon has collected on you from a web browser:

1. Go to from any browser and log into your account.

2. Click Account.

3. Select Account Settings.

4. Click Privacy Settings.

5. Click Manage Settings under Custom Experience Settings.

6. Click Reset.

7. Go back and click Manage Settings under Custom Experiences Plus.

8. Click Reset.

You can learn more about , and .

Correction, April 19: This has been corrected to state that Verizon does not sell customer data to third-party advertisers.