Which service branch does the rank of W-2 belong to?

The rank of W-2 refers to a Chief Warrant Officer 2, which is a position found across various service branches in the U.S. military. While both the Army and Marine Corps use the W-2 rank designation, in the context of the Coast Guard, the equivalent warrant officer ranks also include the W-2 designation.

It's essential to understand that all the branches use this designation, but if we are focusing on one particular service branch associated with the W-2 rank, the Coast Guard is the answer in the context where it typically could overlap with specialized roles and functions within that service. The other branches would have their own similar ranks and systems but are not as primarily associated, especially in this context of question phrasing.

In sum, Coast Guard's rank structure includes the Chief Warrant Officer designations, and the W-2 rank aligns with their operational structure, highlighting the unique role warrant officers play which can differ across service branches.