The European Commission is reportedly looking into antitrust violations by Apple related to the distribution of iPhones and iPads, following informal complaints from mobile operators.

Reuters sources said several operators have spoken to the Commission about their concerns related to the handset subsidy and marketing deals that Apple negotiates with operators.

A European Commission spokesman said on Friday that competition regulators had been informed of concerns about Apple’s distribution approach and that the Commission is “actively monitoring developments in this market”.

However, no formal complaint has been made.

An Apple spokeswoman told Reuters that the company’s contracts “fully comply with local laws wherever we do business, including the EU”.

Operators in the US and Europe pay significant subsidies to smartphone makers, allowing them to offer customers discounts on devices in exchange for tying them to two-year phone contracts.

Apple has commanded higher up-front fees due to its dominant position in the smartphone market. The subsidies paid to Apple have even impacted operator profits, most recently those of China Telecom.

However, Samsung’s recent emergence as the world’s largest smartphone vendor has meant that Apple’s leverage when negotiating subsidies and marketing support is declining.

According to Reuters, US authorities are unlikely to investigate Apple’s practices due to a differing regulatory approach and a recognition that Apple’s market position has weakened.