One of the federal agencies that must sign off on the proposed merger between Sprint and T-Mobile is the Committee on Foreign Investment in the U.S. (CFIUS), and that agency has become a more important factor in recent international merger-and-acquisition action.

Indeed, under the Trump administration and led by Treasury Secretary Steven Mnuchin, the CFIUS played a critical role in ultimately blocking Broadcom’s attempted hostile takeover of Qualcomm over national security concerns.

As Bloomberg reports, such concerns may well factor into the proposed merger of Sprint and T-Mobile, largely due to the holdings of Sprint parent SoftBank. Specifically, the publication noted that SoftBank is the biggest shareholder in China’s Alibaba; that Taiwan’s Foxconn is an investor in the Vision Fund from SoftBank’s Masayoshi Son; and that China’s Huawei is a SoftBank equipment supplier.

To be clear, CFIUS M&A reviews are kept secret and it’s unclear how the agency might ultimately view the merger of Sprint with T-Mobile—both companies said they have no Chinese equipment in their networks, and the combined company will be majority owned by Germany’s Deutsche Telekom. Moreover, as Bloomberg noted, SoftBank obtained CFIUS approval last year of its acquisition of financial company Fortress Investment Group.