Goldman Sachs says recent US involvement in supporting Japan’s yen underscores why the US dollar is difficult to replace as the world’s primary currency. The firm points to Washington’s more hands-on approach to parts of the Treasury market, suggesting that this level of engagement can raise questions among investors and central banks about their willingness to continue holding and relying on dollar assets. In parallel, the analysis links US actions affecting Japanese currency conditions to broader market implications, arguing that currency stability initiatives and liquidity backstops—particularly those tied to US financial markets—illustrate the interconnected role of US policy and dollar funding. Overall, the sources frame the issue as one of global market structure: dollar liquidity and the depth of US Treasury markets make the dollar central to cross-border finance. While the outlets do not provide additional policy details beyond this characterization, they present the view that dollar dominance persists because alternatives face constraints in liquidity, market size, and institutional support.