Dollar Share Decline Doesn't Necessarily Mean Central Banks Are Buying Bitcoin

The global dollar share of official foreign-exchange reserves has been declining since 2015, but this trend may not necessarily indicate that central banks are buying Bitcoin. According to a New York Fed analysis from September 2026, the decline in the dollar share is largely due to changes in reserve sizes and currency mixes among countries.

The researchers used IMF COFER data to show that between 2015 and 2025, the dollar share fell from 64% to 56%. However, this decline was not uniform across all countries. In fact, some countries with below-average dollar allocations saw their reserves grow, pulling down the global average.

The analysis highlights the importance of distinguishing between changes in reserve sizes and currency mixes, and actual investment decisions by central banks. It notes that a country can change its currency mix or accumulate reserves without necessarily cutting its dollar allocation.

The researchers also point out that even when a central bank buys Bitcoin, it may not necessarily be counted as an official reserve. For example, the Czech National Bank's $1 million digital-asset test portfolio in 2025 was explicitly outside international reserves.