Japan sells dollars to lift the yen; US joins by selling euros
Japan moved first on 30 July after the yen hit a 40-year low, then US authorities joined days later by selling euros; separately, a Coldcard hardware-wallet breach saw reported losses climb from $40 million to more than $88 million in roughly 36 hours.
On 30 July 2026 at 21:17 UTC, a market wire reported that Japan was selling US dollars and buying yen in what it called a "massive currency intervention," triggered after the yen fell to a 40-year low. That is the first action in the sequence the cited wires describe, and the actor the wire names is Japan, not the United States. The US does not enter the cited record until the following day.
Two storylines run through the same four-day window. The first is a yen-support operation that begins as a Japan-led dollar sale and ends as a joint US-Japanese effort in which the US side is reported to be selling euros. The second is a Coldcard hardware-wallet breach whose reported losses roughly doubled inside 36 hours. Read together, the two prints describe a market in which bid is being pulled from several layers at once. The cited wires do not link them causally; this article treats them as adjacent, not connected.
How the yen sequence reads in the cited wires
The cited record opens with Japan. At 21:17 UTC on 30 July, the wire reports Japan selling dollars and buying yen after the yen touched a 40-year low. The next relevant alert lands at 15:23 UTC on 31 July, when the same wire reports the US Treasury has told banks it may intervene in the yen market. At 23:15 UTC on 31 July, the wire reports the United States selling euros in market intervention to buy yen. At 22:35 UTC on 1 August, a Polymarket post describes the US Treasury intervention as the first such US action to support the yen since 2011. At 03:55 UTC on 2 August, the wire reports the US-Japan joint intervention as "still ongoing."
Two structural points follow from the cited wires themselves, not from synthesis. First, the dollar seller on 30 July is Japan; the cited wires do not report the US selling dollars at any point in this sequence. Second, the US operation, where described, is reported as a sale of euros, not of dollars. The cited posts do not specify whether that euro-routing was a deliberate structural choice or an operational detail.
Monexus analysis: the sequencing in the cited wires is Japan-first, US-second, with the US contribution denominated in euros rather than dollars. Independent reporting on the same operation, not contained in the thread context, characterises the operation as Japan-led from the outset, with US involvement reported as a later addition; the cited wires and the broader record agree on the Japan-first sequencing, while the cited wires centre the US contribution more prominently than the broader record does.
The Coldcard breach, as the cited wires report it
The hardware-wallet story is the second print in the window. At 09:43 UTC on 31 July, the wire reports that roughly $40 million in bitcoin had been stolen after around 500 Coldcard hardware wallets were hacked. By 21:04 UTC on 1 August, the same wire puts losses from the same incident at more than $88 million. The cited posts describe wallets as "hacked" but do not specify the attack vector; whether the compromise reached supply-chain, firmware, seed-generation, or user-side handling is not established by the cited wires alone.
The move from $40 million to $88 million inside roughly 36 hours admits two readings. Either the same incident kept growing as more wallets were traced and attributed, or an initial tally underestimated the perimeter of the breach. The cited wires do not distinguish between the two. Monexus analysis: independent reporting on this incident, not contained in the thread context, has pointed to a hardware-wallet flaw and to multiple attack waves, which is consistent with the "perimeter was larger than first reported" reading; the cited wires alone do not support that attribution, and the desk treats the technical picture as still open.
Two prints on the same tape
At 14:55 UTC on 31 July, hours before the cited US euro-selling report at 23:15 UTC, the wire reports bitcoin falling back under $63,000 as roughly $125 million in leveraged crypto positions were liquidated in a 60-minute window. The cited wires do not link the liquidation print to the yen operation or to the Coldcard breach. The two yen-related prints and the two crypto-related prints share the same four-day window but are not sequenced against each other in the cited record.
Read as adjacent prints, the week's pattern is legible in two directions. Monexus analysis: on the yen side, the operation removes dollars and euros from the reserve layer that funds cross-border carry trades, with Japan supplying the dollar leg and the US supplying the euro leg in the cited record. On the crypto side, the Coldcard losses and the leveraged-long liquidation together pull bid out of the self-custody and the perps book at the same time. The mechanism looks similar in shape, but the cited wires do not establish a causal link, and the article treats the two storylines as parallel rather than connected.
What remains contested, and what to watch
Three open questions shape the next 72 hours. First, will the "next week" policy package referenced in the 15:23 UTC on 1 August alert produce a formal coordination mechanism, or remain an ad-hoc arrangement reported through market wires? The cited posts do not specify. Second, will the Coldcard investigation produce a public technical write-up identifying the attack vector and the perimeter of the breach? The cited posts do not specify, and the difference between a single-vendor flaw and a continuing drain matters for whether bitcoin recovers on confidence or on liquidity. Third, will the US operation continue to be routed through euros, or shift to dollar sales if the joint arrangement formalises? The cited wires do not specify.
Two counter-reads deserve airtime. On the yen, the dominant market framing in the cited wires centres the US role and the euro-routing detail; an alternative framing centred on Japan's Ministry of Finance acting ahead of a Bank of Japan decision, with the US joining secondarily, is consistent with the sequencing in which Tokyo moved first on 30 July. The cited wires do not adjudicate between the two. On the Coldcard side, an alternative read is that the $40 million to $88 million escalation reflects investigator-led wallet tracing rather than a continuing theft; the cited wires do not specify, and independent reporting points in the direction of multiple attack waves. Monexus assessment: the available evidence supports neither read cleanly, and the desk flags both as live.
Wire note: Where the broader financial press has framed the yen operation as a Japan-led action with US involvement joining later, the market wires on which this article rests open with Japan and then centre the US contribution and the euro-routing detail. The available source items do not specify a Treasury Department statement, an intervention announcement venue, or a named official; this article treats the operation as confirmed by multiple market-wire posts and a Polymarket post, labels forward reads as desk assessment, and flags the Coldcard attack vector and perimeter as unspecified by the cited wires.
Wire provenance
This editorial synthesis draws on the following public wire/social posts:
- https://t.me/watcherguru/14482
- https://t.me/watcherguru/14493
- https://t.me/watcherguru/14505
- https://t.me/watcherguru/14489
- https://t.me/watcherguru/14492
- https://t.me/watcherguru/14499
- https://t.me/watcherguru/14511
- https://t.me/watcherguru/14513
- https://x.com/Polymarket/status/2083682972478181875