Coinbase denies hiding hacks as investor claims $25M loss

What happened

Ari Paul, founder of BlockTower Capital, said on September 29 that Coinbase "lost" $25 million belonging to his firm. He wrote that the loss was first described as Coinbase having "lost" the funds, but that his own investigation led him to a different conclusion.

The dispute began on September 26, when a trader posting as Kuno said Coinbase stole $1.2 million from them a year earlier. Kuno said they had opened more than 30 support tickets and gave the exchange 24 hours to fix it, before posting a call recording and taking legal action.

Coinbase product head Jordan Fish, known as Cobie on X, replied that he could not find any account matching that description and suggested the post may have been engagement bait for a meme token. Coinbase Support later said it had sent Paul a direct message on X.

Coinbase responded through its support account, saying it could not comment on specific clients and that it is not hiding a series of hacks and did not lose $1B. Justin Mart, who previously worked in corporate development and ventures at Coinbase, questioned Paul's account.

Why it matters

The claim puts a large alleged loss at the center of a dispute that Paul says remains tied to multiple legal proceedings. Paul has not made any evidence public, and Unchained has not independently verified his claims. Coinbase has denied hiding hacks.

Coinbase has documented security incidents that give context to the debate. Those incidents do not establish Paul's allegation that the exchange covered up more than $1 billion in losses.

What the data shows

The figures in the dispute include Paul's $25 million claim, Kuno's $1.2 million claim, and Paul's statement that he traced the matter to at least a dozen other firms and more than $1 billion in concealed losses.

Other numbers reported include the $375 million deal that brought Fish to Coinbase, a breach that hit at least 69,400 users in May 2025, a $20 million ransom demand Coinbase says it turned down, and one user's claim of about $45,000 in lost access.

Background

Coinbase disclosed in May 2025 that a breach hit at least 69,400 users. The attacker bribed customer support staff to gain internal access, and the campaign ran from December 2024 until it was discovered in May. Coinbase says it turned down a $20 million ransom demand to delete the stolen data.

In a separate case, ZachXBT accused Tiffany Milanovich in August of involvement in at least $5 million in thefts, including a $500,000 drain of a Coinbase account in October 2025.

What is still unclear

• Paul said he could not share proof because "multiple legal processes" were still unfolding, and alleged that Coinbase had tried to sue him into silence.
• Unchained could not verify claims from other users who described account problems in replies to Paul.
• After Kuno's 24-hour deadline passed, there was no indication of whether legal action was taken or whether the exchange reached out.

Questions readers ask