Key TakeawaysBitcoin plummeted beneath the $73,000 threshold following U.S. military strikes targeting an Iranian installation near the strategically vital Strait of Hormuz.Approximately $1 billion worth of leveraged cryptocurrency positions faced forced liquidation within a single trading day, with long positions comprising 93–94% of losses.BlackRock’s Bitcoin ETF experienced $527.8 million in withdrawals, contributing to an aggregate $733.4 million exodus from Bitcoin spot ETFs on May 27.Ondo token plummeted more than 11% during the session, extending its decline to 25% from the May 22 high.The aggregate cryptocurrency market capitalization contracted 1.66% to reach $2.43 trillion, erasing over $40 billion in value.Military strikes conducted by the United States against Iranian targets created ripple effects across international financial markets on Thursday, with Bitcoin experiencing one of its most pronounced single-session declines in recent memory. The convergence of escalating geopolitical conflict and substantial institutional capital withdrawal drove the wider cryptocurrency ecosystem toward a crucial technical threshold.Bitcoin Experiences Sharp Decline Amid Escalating Middle East ConflictBitcoin was changing hands at approximately $72,978 during Asian trading sessions on Thursday. This represented a 3.4% decline across the previous 24-hour period and a more substantial 6.3% downturn over the preceding seven-day window.Bitcoin (BTC) PriceThe catalyst behind the selloff was a U.S. Central Command military operation targeting an Iranian military facility positioned near the strategically important Strait of Hormuz. U.S. military forces additionally intercepted four Iranian attack drones that were launched toward a commercial maritime vessel. According to a U.S. official, the military response was characterized as defensive in nature and designed to preserve an existing ceasefire arrangement established the previous month.BREAKING: Iran's IRGC releases a statement saying that it has retaliated to the US strike on an Iranian military position in the Strait of Hormuz by attacking a US airbase in Kuwait.In their statement, the IRGC says "aggression will not go unanswered."Oil prices are up nearly…— The Kobeissi Letter (@KobeissiLetter) May 28, 2026Iranian forces retaliated by launching strikes against the airbase from which the U.S. operations originated, based on statements attributed to the Islamic Revolutionary Guard Corps. Kuwait also confirmed it was addressing hostile missile and drone activity within the broader region.During a cabinet meeting, President Donald Trump emphasized that the strait would continue operating without restrictions. “It’s international waters,” he stated. “The strait’s going to be open to everybody.”The military developments reversed weeks of growing market optimism surrounding potential ceasefire progress. Bitcoin had maintained support above the $74,000 level despite multiple earlier headlines concerning Iran. Thursday’s strikes shattered that support zone.Ethereum declined 4.2% to settle at $1,976, falling beneath the psychologically significant $2,000 threshold. Solana retreated 3.5% to $80.57, XRP decreased 3.6% to $1.28, and Dogecoin shed 3.2% to reach $0.0979. Hyperliquid stood as the sole major token maintaining a weekly gain, despite experiencing a 4.5% daily decline.Institutional ETF Withdrawals Intensified Downward MomentumInstitutional capital flight amplified the market downturn. Bitcoin spot exchange-traded funds registered net withdrawals totaling $733.4 million on May 27. BlackRock’s flagship Bitcoin fund alone witnessed $527.8 million in single-day outflows.Crypto ETF Flows — May 27 ETF demand stayed weak for the majors yesterday.$BTC: -$733M$ETH: -$67M$SOL: +$1MSolana was the only one to finish in positive territory. pic.twitter.com/sQmshBwxeh— CoinCentral (@realcoincentral) May 28, 2026This institutional selling directly contributed to the liquidation avalanche. Bitcoin represented $386 million of the forced position closures, with Ethereum accounting for $246 million. The most substantial individual liquidation involved a $15.34 million Bitcoin position on the Hyperliquid platform.Source: CoinglassAccording to CoinGlass analytics, $958.8 million in aggregate liquidations affected 167,706 individual traders during the 24-hour measurement period. Approximately 93% of these liquidations involved long positions — market participants who had wagered on continued price appreciation.Broader Altcoin Performance and Technical Market StructureThe total cryptocurrency market capitalization contracted 1.66% to $2.43 trillion, eliminating roughly $40.91 billion in value. This positions the market precisely at the 0.618 Fibonacci retracement level of the rally spanning late March through the May peak of $2.72 trillion.Ondo emerged among the session’s worst performers, tumbling over 11%. This extended a 25% deterioration from its May 22 peak of $0.47.On the Bitcoin technical chart, prices settled between the 0.5 Fibonacci level at $73,871 — which had already been breached — and the 0.618 level at $71,765. Selling volume accompanying the most recent bearish candles diminished relative to earlier phases of the decline, potentially signaling that downward momentum may be moderating near this technical zone.A daily closing price beneath $71,765 would establish a pathway toward the $68,766 support zone. Conversely, a recovery surpassing $75,978 would reestablish the trajectory toward $78,584.The velocity of Thursday’s liquidation cascade indicates traders were positioned for continued recovery when market dynamics reversed course unexpectedly.The post Bitcoin (BTC) Plunges Below $73K as U.S.-Iran Tensions Trigger Massive Crypto Selloff appeared first on Blockonomi.