@coingecko released a report on $BTC ETF (USA) and these are the numbers:
Spot Bitcoin (BTC) exchange traded funds (ETFs) in the US hold $27.0 billion in BTC as of January 17. The majority of assets under management (AUM) is held by the Grayscale Bitcoin Trust (GBTC), with $25.3 billion. This accounts for 93.4% of all BTC held in US spot Bitcoin ETFs. However, it should be noted that GBTC was started in 2013, and thus has had a 10-year headstart from the new ETFs.
Grayscale saw $1.3 Billion worth outflows after converting to a spot ETF. 🧵 ⏬
https://www.coingecko.com/research/publications/us-spot-bitcoin-etfs