German engineering giant Siemens and the US tech giants Apple and SAP have joined in denouncing proposed EU legislation governing the use of data produced by smart devices and other consumer goods.

Before the Data Act can be enacted as law, EU member states and EU legislators are working on its specifics. It was first suggested by the European Commission last year.

The draft rule, which addresses corporate and consumer data from the EU, is one of several pieces of legislation designed to restrain the influence of American tech titans and aid the EU in achieving its digital and environmental goals.

"It risks undermining European competitiveness by mandating data sharing - including core know-how and design data - with not only the user, but also third parties," the companies wrote in a joint letter to Commission President Ursula von der Leyen, EU antitrust chief Margrethe Vestager and EU industrial chief Thierry Breton.

"Effectively, this could mean that EU companies will have to disclose data to third-country competitors, notably those not operating in Europe and against which the Data Act's safeguards would be ineffective," they said.

The draft rule has drawn criticism from the United States for being overly onerous, and German businesses have voiced concern that a section requiring businesses to exchange data with third parties in order to provide aftermarket or other data-driven services could jeopardize trade secrets.

The letter demanded measures so that businesses could decline requests for data sharing when trade secrets, cybersecurity, health, and safety are at danger, and it also urged lawmakers not to broaden the list of devices covered by the law.

The companies argued that the Act should protect contractual flexibility by allowing customers and providers to agree on contracts that are optimal for each business case in relation to a clause that permits customers to migrate between multiple cloud providers.