Brussels Made You Share the Data. It Did Not Make You Define It

The EU Data Act grants users the right to the data their machine generates. It is silent on whose definition of "the data" governs once it leaves the building.

On 12 September 2025 the core provisions of the EU Data Act began to apply. The regulation gives users of connected products and related services the right to access the data those products generate and to have it shared with a third party of their choosing, and it sets rules for switching between cloud providers. The European Commission frames it as ensuring connected devices are "designed to allow data sharing." The obligation to share is now law. The obligation to agree on what the shared fields mean is not.

This matters because access is the easy half. A sensor reading, a usage event, a "session" can each mean three different things across the manufacturer, the holder, and the recipient who just exercised a statutory right. The Act creates a counterparty who is entitled to your feed and has no obligation to inherit your assumptions. Cross-organization sharing turns every quiet internal ambiguity into an external contract dispute, on a schedule set by the regulator rather than by your roadmap.

What it reveals is that data sharing was never blocked by a missing pipe; it was blocked by a missing owner of the definition. A mandate can compel the transfer and still leave the semantics ownerless, which is the precise condition under which two parties exchange records and discover, months later, that they were never describing the same thing. The law moved the data. The meaning stayed exactly where it was: unassigned.

Watch which companies respond with a documented data dictionary and which respond with a wider pipe. Watch the contracts, where definitions, units, and refresh semantics either get named owners or get deferred to "as provided." And watch the 12 September 2026 design obligations, when products placed on the market must be built to share by default, and the undefined field becomes a manufacturing decision instead of a meeting agenda item.