Jane Street reported more than $1 billion in U.S. spot Bitcoin ETF shares as of June 30, 2026, according to a quarterly regulatory filing released in August.

The quantitative trading firm’s largest disclosed position was BlackRock’s iShares Bitcoin Trust, or IBIT. Jane Street reported roughly $828 million of IBIT shares in its second quarter filing.

The remaining exposure was distributed among other U.S. listed products. Those holdings included Fidelity’s Wise Origin Bitcoin Fund and Grayscale’s Bitcoin Trust. The combined value of Jane Street’s reported spot Bitcoin ETF shares exceeded $1 billion at the quarter’s close.

The disclosure concerns shares issued by investment funds. It does not establish that Jane Street directly owned the Bitcoin held by those funds.

Jane Street’s IBIT position rebounded during the quarter

Jane Street’s approximately $828 million IBIT position represented a sharp recovery from the previous quarter. At March 31, the firm reported about 5.9 million IBIT shares valued near $225 million.

The earlier reduction attracted attention because Jane Street had held more than 20 million IBIT shares at the end of 2025. As crypto.news reported, the firm reduced several fund positions while expanding its Ether exposure during the first quarter.

The second quarter filing indicates that Jane Street rebuilt its reportable IBIT position by June 30. However, changes in reported value can reflect both share transactions and movements in the fund’s market price. A Form 13F does not disclose when the shares were acquired or the prices paid.

The filing also cannot establish Jane Street’s motive. The firm is a major quantitative trader and liquidity provider in exchange traded products. Its holdings may support market making, arbitrage, hedging or other trading activities rather than a long term directional position.

The $1 billion disclosure does not equal direct Bitcoin ownership

Spot Bitcoin ETFs hold Bitcoin through fund custody arrangements while investors trade shares on regulated securities exchanges. Jane Street’s filing therefore reports ownership of securities rather than coins controlled through the firm’s blockchain addresses.

This distinction also means the filing cannot be converted directly into a specific amount of Bitcoin owned by Jane Street. Each fund has its own share count, net asset value and Bitcoin holdings. Jane Street’s position represents an economic interest in the funds at the reporting date.

Form 13F provides only a partial view of an institutional manager’s activity. SEC guidance requires covered managers to report the number and quarter end value of eligible securities, including ETF shares.

The reports do not provide a complete trading book. Short sales and many derivatives are absent. Separate put and call positions may appear when reportable, but they still do not reveal how each position interacts with the manager’s other trades.

Consequently, the filing does not prove Jane Street held more than $1 billion of unhedged exposure to Bitcoin. It only confirms that its reportable long ETF shares crossed that level on June 30.

U.S. institutions continue using regulated Bitcoin funds

Jane Street’s disclosure adds to evidence that major financial firms use U.S. spot Bitcoin ETFs for trading, portfolio exposure and liquidity management. BlackRock’s IBIT has repeatedly appeared as the largest crypto fund position in institutional reports.

Other institutions have also disclosed material IBIT holdings. In related coverage, Abu Dhabi’s Mubadala raised its reported position to approximately $566 million during the first quarter of 2026.

Banks have reported smaller positions through the same regulatory process. Barclays, for example, disclosed approximately $131 million of exposure in an earlier filing.

Those disclosures do not necessarily represent comparable strategies. A sovereign investor, bank, hedge fund and market maker can hold the same ETF shares for different reasons. Form 13F provides position data but does not require managers to explain their investment purpose.

No verified market reaction could be attributed specifically to Jane Street’s filing. Bitcoin and ETF prices also respond to fund flows, macroeconomic news and wider market positioning.

The next filing will show Jane Street’s September holdings

Jane Street’s next Form 13F will provide a snapshot of reportable positions held on Sept. 30. The SEC lists Nov. 16, 2026, as the filing deadline for third quarter reports.

That disclosure will show whether the firm maintained, expanded or reduced its Bitcoin ETF shares by quarter end. It will not reveal any changes made after Sept. 30 or positions closed before the reporting date.

Investors should therefore treat the current report as historical information. The June 30 holdings may have changed before the filing became public, and Jane Street’s undisclosed hedges could materially alter its net exposure.

Bitcoin rose above $64,000 on Tuesday, up over 1% on the day and marginally higher on the week, the only major with a meaningful gain as the rest of the market drifted lower.

Ether eased half a percent to just under $1,900, though it holds an almost 1% weekly gain. XRP fell over 1% to just under $1 and is down over 2% on the week, the weakest of the group. Dogecoin dropped almost half a percent to 7 cents, BNB and tron both slipped marginally to just over $600 and 33 cents, and solana was flat at just under $76.

Hyperliquid’s HYPE was the exception among the smaller majors, up almost 1% to just over $59 and 7.5% over seven days, by far the strongest weekly performance.

Alex Kuptsikevich, chief market analyst at FxPro, said bitcoin has now spent four days below its 50-day moving average after an earlier attempt to break above it, and remains below its 200-week average on the longer view. That puts sellers in control on both the medium and very long-term trends, he said, and nothing changes until the price leaves the $62,000 to $65,000 range it has been stuck in.

Payward, the parent company of cryptocurrency exchange Kraken, joined Anthropic’s Project Glasswing on Aug. 17 and gained restricted access to Claude Mythos 5 for defensive cybersecurity work.

The company plans to use the artificial intelligence model to scan its software environments for vulnerabilities over the coming weeks. Findings will enter Payward’s existing security review process rather than automatically producing software changes.

Payward also said it intends to disclose validated vulnerabilities affecting third party open source projects to their maintainers. The company did not identify its first scanning targets, publish a deployment schedule or disclose the cost of its Mythos 5 access.

Payward will scan its software environments

Payward said Claude Mythos 5 will examine all company environments for software weaknesses. Its infrastructure supports digital asset trading, custody and settlement services that remain available continuously.

The announcement does not specify whether Mythos 5 will receive access to production systems, isolated copies of source code or controlled testing environments. Payward also did not describe how its security team will validate findings before approving fixes.

False positives remain a practical concern when artificial intelligence systems review complex software. A model may identify unreachable code, duplicate an existing report or misunderstand how a component operates in production. Human review is therefore required before teams classify an issue as a vulnerability.

The Ethereum Foundation reached a similar conclusion while testing AI security agents. As crypto.news reported, its researchers found that AI generated vulnerability reports still required independent human validation, particularly when agents examined complex protocol code.

Payward cochief executive Arjun Sethi said AI could change the imbalance between attackers and defenders by reading code at greater scale.

“A model can read every line of code the way an attacker would, at machine scale, so we find the flaw before anyone can build the exploit,” Sethi said.

The statement describes Payward’s intended defensive advantage. The company has not yet published results showing how many valid flaws Mythos 5 found within its systems.

Project Glasswing restricts access to vetted partners

Anthropic launched Project Glasswing in April 2026 to give selected infrastructure providers and software maintainers early access to its strongest cybersecurity models.

Initial participants included Amazon Web Services, Apple, Cisco, CrowdStrike, Google, JPMorganChase, Microsoft, Nvidia, Palo Alto Networks and the Linux Foundation. Anthropic later expanded the initiative to approximately 150 organizations across more than 15 countries.

The company says participating organizations must meet security requirements before receiving access. Mythos 5 is not generally available because the same capabilities used to identify vulnerabilities can also help produce working exploits.

As previously reported, Anthropic restored Mythos access only to vetted U.S. organizations after the U.S. government lifted temporary export restrictions. The safeguarded Claude Fable 5 model returned to wider availability.

Payward said its access followed the U.S. decision allowing Mythos 5 to reach organizations that operate and defend critical infrastructure. Anthropic’s official model page confirms that access was restored for a set of U.S. organizations following government approval.

Neither Anthropic nor the U.S. government has publicly designated every digital asset platform as critical infrastructure. Payward’s statement that such platforms “belong on that list” represents the company’s position rather than a formal government classification.

Claude Mythos 5 carries defensive and offensive risks

Anthropic describes Claude Mythos 5 as its most capable model for cybersecurity and biology research. The model can inspect code, identify weaknesses, suggest patches and assist approved researchers with testing exploit paths.

Project Glasswing’s earlier Mythos Preview reportedly found more than 10,000 flaws classified as high or critical severity across widely used software. Anthropic’s coordinated disclosure dashboard showed 1,596 vulnerabilities reported across 281 open source projects as of May 22.

Those figures are Anthropic’s measurements and do not mean every initial model finding was valid. Its dashboard recorded a 90.8% true positive rate among 1,900 candidates reviewed by external security firms.

Anthropic said independent human triage remains the limiting stage. Only 97 listed findings had been patched upstream at the time of the dashboard update, while 88 had received a public advisory identifier.

The model can also create exploit components and combine them into attack chains. Anthropic cited this dual use capability when explaining why Mythos 5 remains limited to approved partners.

In related coverage, researchers found that Mythos class models could turn software flaws into working exploit chains. Wider access would therefore give attackers some of the same capabilities available to defenders.

Open source findings will go to maintainers

Payward said vulnerabilities discovered in shared third party code will be sent to the relevant project maintainers. It presented that process as a way to protect other organizations using the same software.

The company did not publish a coordinated disclosure policy for the initiative. Important unanswered details include how long maintainers will have to patch flaws, which findings Payward may disclose publicly and how it will handle projects that do not respond.

Responsible disclosure normally requires researchers to verify a vulnerability, contact the maintainer privately and allow time for remediation before releasing technical information. Premature publication can expose users before a patch becomes available.

Payward has previously faced disputes over security research. As crypto.news reported, Kraken patched a deposit flaw that researchers used to withdraw nearly $3 million. The exchange later recovered the funds following a public disagreement with CertiK.

That episode was unrelated to Project Glasswing, but it shows why clear testing and disclosure rules matter. AI scanning can increase the number of reported findings, creating additional work for security teams and maintainers.

What happens next for Payward’s AI security rollout

Payward plans to begin scanning its environments within weeks. The next verifiable updates would include confirmed vulnerabilities, completed patches or public disclosures coordinated with affected open source projects.

No performance targets were announced. Payward did not say how frequently Mythos 5 will scan its systems or whether the model will review new code before deployment.

Anthropic requires Mythos 5 customers to accept thirty day data retention for safety monitoring. Payward has not explained what code or system information will be submitted, how sensitive data will be separated or whether customer information falls outside the scanning process.

For now, the confirmed development is Payward’s admission to Project Glasswing and planned use of Claude Mythos 5. Whether the model improves the company’s security will depend on the quality of its findings, human verification and the speed of subsequent patches.

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