The spot bitcoin exchange-traded funds of BlackRock and Fidelity already have an edge over Grayscale Bitcoin BTC -2.54% Trust (GBTC) — the largest fund by assets under management — at least in two liquidity metrics, according to JPMorgan.

The first metric is JPMorgan's proxy for market breadth, based on the Hui-Heubel ratio. This metric is lower for BlackRock and Fidelity ETFs by around four times, implying that these two ETFs show significantly more market breadth than GBTC, JPMorgan analysts led by Nikolaos Panigirtzoglou wrote in a report on Wednesday.

The second metric is based on measuring how much ETF closing prices deviate from their net asset value on average. This metric suggests that the ETF price deviation from the NAVs of the Fidelity and BlackRock spot bitcoin ETFs approached that of the SPDR Gold Shares ETF in the most recent week, implying a significant improvement in liquidity, the analysts said. Meanwhile, the deviations for the GBTC ETF have remained higher, indicating lower liquidity.

While those two metrics do not capture all dimensions of market liquidity — particularly market depth — there is already evidence that BlackRock and Fidelity's bitcoin ETFs have an advantage over GBTC in certain liquidity metrics related to market breadth, the analysts noted.

The analysts also pointed out that if GBTC fees aren't reduced, the fund will likely see more outflows and lose funds to other ETFs, especially BlackRock and Fidelity's bitcoin ETFs.