Representatives of Elon Musk’s Department of Government Efficiency have been working at the Centers for Medicare and Medicaid Services

Representatives from Elon Musk's Department of Government Efficiency (DOGE) have been working at the Centers for Medicare and Medicaid Services (CMS), gaining access to key payment and contracting systems, according to a Wall Street Journal report on Wednesday that cited sources familiar with the matter.

DOGE officials have been on site at CMS headquarters this week, reviewing both the agency’s technology and the spending that flows through its systems. Their focus is on identifying what they deem to be fraud or waste, the report said. They are also evaluating the agency’s organizational structure and staffing.

Musk, who chairs the newly created DOGE, commented on the WSJ report via X, claiming without evidence that "this is where the big money fraud is happening."

Musk, an ally of U.S. President Donald Trump and the world’s richest man, has been tasked by Trump with rooting out waste and fraud across federal agencies.

CMS oversees Medicare, which provides health coverage for older and disabled Americans, and Medicaid, which serves lower-income individuals—together covering over 140 million U.S. citizens. While CMS regularly faces issues with improper payments, these can stem from fraud, abuse, or administrative errors by states, contractors, or providers.

On Wednesday, CMS confirmed its collaboration with DOGE, saying it was ensuring proper access to its systems and technology.

"We are taking a thoughtful approach to identify opportunities for more effective and efficient use of resources while remaining aligned with President Trump’s goals," CMS said in a statement.

When asked about the WSJ report, White House representatives did not address specifics but defended Musk’s work with DOGE, emphasizing the administration’s commitment to improving government accountability.

According to the Wall Street Journal, one of the systems accessed by DOGE representatives is the CMS Acquisition Lifecycle Management system, which contains information on federal contracts. However, sources noted that DOGE staff have not been given access to databases containing personal health information of Medicare or Medicaid enrollees.

The DOGE’s access is “read-only,” meaning they cannot modify any systems, the report said.

Separately, the U.S. Treasury confirmed on Tuesday that Musk’s team has been granted "read-only access" to its payment system codes. However, it denied any disruption to government payments, including those for Social Security and Medicare.