President Donald Trump announced on Truth Social that his administration is opening a Section 301 investigation into the European Union in response to fines levied on US companies, including a recent €890 million ($1 billion) fine on Google. Trump claims the Section 301 investigation will reverse the EU’s penalties and likely lead to “a substantial TARIFF.”

“The United States of America is not a ‘PIGGYBANK’ for Europe, nor will we allow it to be,” Trump writes. “Please let this TRUTH serve to represent that we will immediately initiate a 301 Investigation into the practice of ‘ROBBING’ American Companies and, in turn, the American Taxpayer.”

The European Commission fined Google $1 billion for using Google Search to unfairly promote its own travel and shopping tools, and preventing developers from advertising alternative payment options in the Google Play Store. Both actions violated the Digital Markets Act, a broad-reaching 2022 regulation that the EU has used as justification to fine companies like Meta, Apple and now Google.

Since the Supreme Court struck down Trump’s earlier global tariff regime in February, the Trump administration has relied on Section 301 of the Trade Act of 1974 as one of several loopholes to introduce new tariffs. The law allows the US Trade Representative to investigate trade partners and apply tariffs when their practices are found to unfairly burden or restrict US commerce. Ironically, like the EU’s fines, Section 301 tariffs can also be challenged in court and overturned.