Benchmark regression.

In order to reveal the impact of pilot free trade zones policy on green development, we use multi-period difference-in-difference estimation and fixed effect model to explore the impact and impact mechanism of the establishment of free trade zones on the green transformation of enterprises from the micro perspective, based on the panel data of China’s A-share listed companies from 2009–2021, The results show that pilot free trade zones policy significantly improves the green transformation of enterprises in the zones. Pilot free trade zones policy affects the corporate green transformation through industrial agglomeration and financial constraints. The green transformation of state-owned enterprises, non-heavy polluting enterprises and high-tech enterprises are significantly impacted by pilot free trade zones policy. Urban innovation and green subsidies play a positive moderating role in the impact of free trade zones on enterprises’ green transformation. The research conclusions provide a valuable policy basis for how to promote the green transformation of enterprises under the free trade zones policy.