Dollar Reserve Decline May Not Indicate Central Bank Selling or Buying

A new analysis by New York Fed researchers has found that a decline in the dollar share of global official foreign-exchange reserves does not necessarily mean that central banks are selling dollars or buying Bitcoin.

The study, published on September 2, 2026, looked at data from 2015 to 2023 and found that changes in reserve sizes can affect the global average dollar share, even if individual countries' allocations remain unchanged.

For example, Switzerland's reserve growth between 2015 and 2019 pushed down the aggregate dollar share, despite its own allocation increasing. Similarly, between 2019 and 2023, the preferences and reserve-size contributions of 62 countries with complete data actually declined by 0.8 percentage points.

The researchers emphasized that reserve-share statistics do not establish sovereign Bitcoin purchases. To determine whether central banks are investing in Bitcoin, separate evidence is needed to show a dedicated allocation for investment purposes, beyond liquidity needs.