So why not Grayscale? According to Cointelegraph

Independent Research Verifies GBTC’s 633K Bitcoins: So Why Not Grayscale?

With digital asset management firm Grayscale refusing to provide proof of reserves for its Grayscale Trust (GBTC), an independent analyst spent days digging through the blockchain to independently verify it. establish its holdings.

OXT Research analyst Ergo used on-chain forensics to confirm that as of November 23, GBTC owns around 633,000 Bitcoins (BTC) is held by its custodian, Coinbase (NASDAQ:) Custody.