6/27/2012: This post has been corrected.

Cellphone companies hold onto your location information for years and routinely provide it to police and, in anonymized form, to outside companies.

As they note in their privacy policies, Verizon, Sprint, AT&T, and T-Mobile all analyze your information to send you targeted ads for their own services or from outside companies. At least tens ofthousands of times a year, they also hand cellphone location information to the FBI or police officers who have a court order.

But ProPublica discovered that there’s one person cell phone companies will not share your location information with: You.

We asked three ProPublica staffers and one friend to request their own geo-location data from the four largest cellphone providers. All four companies refused to provide it.

Here’s how they responded:

Verizon

On releasing location data to you: “Verizon Wireless will release a subscriber’s location information to law enforcement with that subscriber’s written consent. These requests must come to Verizon Wireless through law enforcement; so we would provide info on your account to law enforcement— with your consent— but not directly to you.”

On responding to requests from law enforcement: “ Unless a customer consents to the release of information or law enforcement certifies that there is an emergency involving danger of death or serious physical injury, Verizon Wireless does not release information to law enforcement without appropriate legal process.” A spokesman said being more specific would “require us to share proprietary information.”

Sprint

On releasing location data to you: “We do not normally release this information to customers for privacy reasons because call detail records contain all calls made or received, including calls where numbers are ‘blocked.’ Because of an FCC rule requiring that we not disclose ‘blocked’ numbers, we only release this information to a customer when we receive a valid legal demand for it.”

On responding to requests from law enforcement: “If the government is seeking “basic subscriber information” (defined in 18 USC sec. 2701, et seq) it can obtain that information by issuing a subpoena. If the government is seeking Sprint records relating to our customers that go beyond “basic subscriber information” then the government must furnish Sprint with a court order based on specific and articulable facts. If the government is seeking customer’s content then it must obtain a warrant based on probable cause.”

AT&T

On releasing location data to you: “Giving customers location data for their wireless phones is not a service we provide.”

On responding to requests from law enforcement: "We do share data with law enforcement as part of a valid legal process - for example, a court order or a subpoena."

T-Mobile

On releasing location data to you: “No comment.”

On responding to requests from law enforcement: “For law enforcement agencies, we release customer information only when compelled or permitted under existing laws. This includes, but is not limited to, circumstances under which there is a declaration from law enforcement of an exigent circumstance, as well as other valid legal process, such as subpoenas, search warrants, and court orders.”

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As location tracking by cell phone companies becomes increasingly accurate and widespread, the question of who your location data actually belongs to remains unresolved. Privacy activists in the U.S. say the law has not kept pace with developing technology and argue for more stringent privacy standards for cell phone companies. As Matt Blaze, a University of Pennsylvania professor put it, “all of the rules are in a state of enormous uncertainty and flux.”

The Obama administration has maintained that mobile phone users have “no reasonable expectation of privacy.” The administration has argued against more stringent standards for police and the FBI to obtain location data.

The FBI also says data collected by cell phones is not necessarily accurate enough to pose much of a threat to your privacy— for instance, in a strip mall, cell phone records may not show whether you are in a coffee shop or the apartment next door.

But that is quickly changing. Blaze said as the number of mobile phones continues to rise, cell phone companies are now installing thousands of small boxes known as microcells in crowded places like parking garages and shopping malls to enable them to provide better service. Microcells, he said, also enable the phone companies to record highly precise location data. While your phone is on, he said, it is constantly recording your location.

T-Mobile, Sprint, Verizon and AT&T all refused to disclose how many requests from law enforcement they receive.

Our idea to test whether cellphone companies will give users their own location data came from a German politician who successfully obtained his data last year from Deutsche Telekom. Consumers in Europe have greater protections.