The following is the Sept. 26, 2018 Congressional Research Service report, Marine Corps Amphibious Combat Vehicle (ACV): Background and Issues for Congress.
From the report:
On January 6, 2011, after spending approximately $3 billion in developmental funding, the Marine Corps cancelled the Expeditionary Fighting Vehicle (EFV) program due to poor reliability demonstrated during operational testing and excessive cost growth. Because the EFV was intended to replace the 40-year-old Amphibious Assault...
https://news.usni.org/2018/09/27/report-congress-marine-corps-amphibious-combat-vehicle-program-2