Why Bitcoin bulls shouldn’t mistake a shrinking dollar reserve share for central bank buying

A Sept. 2, 2026 analysis by New York Fed researchers shows how a few large reserve portfolios can lower the global dollar share without a broad retreat from dollars. For investors assessing future sovereign demand for Bitcoin, the distinction is between a changing average and an investment decision.Linda S. Goldberg, Oliver Hannaoui and Sneha Parthasarathy report that the dollar share of global official foreign-exchange reserves fell from 64% at year-end 2015 to 56% at year-end 2025, using IMF COFER data.Their country-level evidence points to concentrated decisions and changes in reserve sizes.Countries can change the currency mix of their portfolios, the “preferences” channel. Alternatively, their total reserves can grow or shrink, changing their weight in the global average.When a country with a below-average dollar allocation accumulates reserves, it can pull down the worldwide dollar share without cutting its own allocation. Switzerland did that between 2015 and 2019: its reserve growth pushed the aggregate share down even as its own dollar allocation rose.For that period, 76 countries had complete endpoint data within a 79-country exercise. Their preferences and reserve-size c...