As you ride your dockless smart bike through the streets of Sydney, it’s worth considering that you’re not alone. In fact, you’re being followed.

The apps the bikes use, and a legal GPS system or bluetooth device, which is linked to the share bikes of Obike, Ofo and Reddy Go, are tracing your movements. These companies know you like to cruise to your local ice-cream shop every Thursday night after dinner. They know you’re late to work most mornings. And they know you barely leave Bondi. Not only do the companies behind share bikes know where you are, you have given them permission to share this and other information with others. And they potentially will. If not now, then possibly in the future.

The controversy around share bikes goes beyond complaints about “public clutter” and vandalism. The startups charge little per ride ($1.99, which is about half the price of a bus fare), which begs the question: how do they stay in business?

Dr Sandra Peter from Sydney Business Insights at the University of Sydney's Business School believes some of these businesses are selling your personal data. On her The Future podcast she says: “There are a number of ways they could be making money. [One is] through the dollar people pay for 30 minutes of riding the bike. You’d think this would be a great source of revenue, turns out it’s not.”

Peter refers to a study by the National Associated of City Transportation Officials that suggests you’d need to ride the bike four times a day for the businesses to make any real profit, which is generally not the case. “And so, another source of revenue is selling data to third-party companies,” says Peter.

This might surprise most people, but it’s all there in the fine print. As soon as you download a smart-bike app, you’re giving smart-bike companies permission to hand over your personal data to third parties. Part of the problem for consumers is that the word “data” is still a vague term.

The information potentially shared by these companies could include personal details such as email address and social-media handles and transport insights.

But who would be interested in buying your information? Peter sites US-based athletes social network Strava in her podcast. It allegedly benefits from receiving transport data. Kai Remier, professor of information technology and organisation at The University of Sydney, reports in the same podcast that, “Strava can [tell transport bodies] where to put in bike lanes, where to build infrastructure and where traffic lights should be changed.”

Obike, Ofo and Reddy Go’s privacy policies specifically state they can share your information with a third party. “We may disclose your personal information to our related entities, affiliates, partners, contractors and associates,” reads Ofo’s user agreement and privacy policy.

The company policy also states it can make money off your information by being “engaged in [a] business asset. We may transfer and/or disclose your personal information to facilitate the due diligence process and the completion of the transactions,” it says on its website.

When Broadsheet spoke to the founder of Sydney’s first ride-sharing service Reddy Go, Donald Tang, he told us his company does not share customers’ information, despite it saying that it has the right to on its website. When Broadsheet questioned this, Tang explained that this is included in the terms and conditions to legally cover the company in the long term. "It's in case we consider introducing data sharing in the future," he says. "But we don't do it now."

Tang says that for the moment Reddy Go has chosen a different business model. “The difference between us and our competitors is we do not collect personal information from the rider,” he told Broadsheet. “Our lock device can generate and report on the location by itself [without data being collected from someone’s smart phone] because each of the locks [attached to the bike’s rear] will contain a sim card,” he says. Every two hours the lock will send a signal to the server with its own anonymous data.

With companies lining up to obtain people’s data, why has Tang decided not to collect? “We don’t want to do it that way. I am concerned with transportation services, not data-sharing services. We define ourselves in a different way,” he says, adding he generates enough revenue via rental costs and that he might consider introducing “soft” digital advertising in the future.

The world’s largest bike-share platform, Mobike, which recently arrived in Sydney, takes a similar approach, it says. “[We] use a sim in the bike and the GPS tracks the distance and location of each trip. The data is not sold, it is used to support the operations and ensure bikes are located in high-use areas,” a spokesperson from the company told Broadsheet.