Cryptocurrency investment product provider Grayscale Investments has refused to provide on-chain proof of reserves or wallet addresses to show the underlying assets of its digital currency products citing “security concerns.”

In a Nov. 18 Twitter thread addressing investor concerns, Grayscale laid out information regarding the security and storage of its crypto holdings and said all crypto underlying its investment products are stored with Coinbase’s custody service, stopping short of revealing the wallet addresses.

6) Coinbase frequently performs on-chain validation. Due to security concerns, we do not make such on-chain wallet information and confirmation information publicly available through a cryptographic Proof-of-Reserve, or other advanced cryptographic accounting procedure.

— Grayscale (@Grayscale) November 18, 2022

“We know the preceding point in particular will be a disappointment to some,” Grayscale added, “but panic sparked by others is not a good enough reason to circumvent complex security arrangements that have kept our investors’ assets safe for years.”

The move by Grayscale comes as pressure mounts on crypto businesses to introduce proof of reserves in the wake of FTX’s liquidity issues and subsequent bankruptcy.

Some Twitter users hit out at Grayscale’s view that security concerns surrounded its decision to withhold its wallet addresses, with one commenting the addresses of Bitcoin (BTC) inventor Satoshi Nakamoto are well known and are of higher value to attackers, “yet Satoshi’s Bitcoin remains secure.”

Grayscale shared a letter co-signed by Coinbase chief financial officer Alesia Haas and Coinbase Custody CEO Aaron Schnarch that broke down Grayscale’s holdings by its investment products and reaffirmed the assets “are secure,” that each product has its “own on-chain addresses” and the crypto always belongs “to the applicable Grayscale product.”

Grayscale added that each of its products is set up as a separate legal entity and “laws, regulations, and documents […] prohibit the digital assets underlying the products from being lent, borrowed, or otherwise encumbered.”

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Grayscale is known for its Grayscale Bitcoin Trust (GBTC), a security tracking the price of Bitcoin, it also has products tracking the price of other cryptocurrencies such as Ether (ETH) and Solana (SOL).

Investor concerns come as Genesis Global, serving as the liquidity provider for GBTC, announced on Nov. 16 that it had halted withdrawals, citing “unprecedented market turmoil” resulting in significant withdrawals from its platform that exceeded its current liquidity.

Genesis is a part of the crypto-focused venture capital company Digital Currency Group (DCG) which also owns Grayscale. GBTC is trading at a discount of nearly 43% compared to its net asset value in part due to investor speculation on GBTC’s exposure to Genesis.