Bitcoin retreated to $83,000 on Monday morning as geopolitical tension over Iran’s Strait of Hormuz sent oil prices spiking above $100 a barrel, triggering a broader risk-off move that hit altcoins far harder than the flagship cryptocurrency. According to reporting by CoinDesk, the selloff represents a near-perfect mirror of Friday’s rally, with the day’s biggest gainers — DeFi tokens and computing-focused projects — reversing course as traditional markets sold off alongside crypto.

The CoinDesk 100, which tracks the 100 largest digital assets outside Bitcoin and Ethereum, dropped 2.6% to 1,874.56, with 91 of its 100 constituents in the red. Bitcoin’s 1.7% decline since midnight UTC paled in comparison to the volatility among smaller tokens. Quant (QNT), which surged 39% on Friday, fell 16% in the unwinding. The Graph (GRT) gave back a 14% gain with a 12% loss, while Ondo (ONDO) reversed an 8% jump with a 12% drop.

Geopolitics Trump Crypto Momentum

The catalyst was unmistakably external to cryptocurrency markets. President Trump rejected Iran’s conditions for reopening the Strait of Hormuz, which included the release of frozen Iranian funds, lifting oil sanctions, and ending the U.S. naval blockade of Iranian ports. Brent crude climbed 3.2% to $100.83, reversing Friday’s dip below that psychologically important level.

The oil move reverberated across risk assets globally. Gold fell 3.3% to $4,144 per ounce. Silver dropped 5.1% to $61. U.S. equity futures weakened, with S&P 500 contracts off 0.44% and Nasdaq 100 futures down 0.95%. The dollar index gained 0.06% to 101.09, a defensive bid typical of geopolitical stress.

Sector Weakness and Positioning Unravels

The DeFi Select Index (DFX) suffered the worst damage, losing 6.4% on Monday and 7.3% over 24 hours despite leading Friday’s advance. The CoinDesk Computing Index (CPUS) slipped 3.2% Monday and 5.0% over the rolling day, a sharp reversal from Friday’s leadership.

Derivatives data suggested traders were actively reducing exposure rather than adding to bets. Bitcoin futures open interest fell to 650,000 BTC, the lowest since March, as leverage unwind continued. Funding rates remained negative across major exchanges, indicating that remaining positions lean bearish. Trading volume jumped 70% to $172 billion over 24 hours, but open interest fell 3% to $150 billion — a pattern that signifies positions being closed rather than fresh capital entering the market.

Ether’s open interest fell to 12.85 million ETH from 13.95 million on July 1, despite ETH rallying 68% since that date. The divergence underscores that spot buying, not leverage, drove the earlier advance. Solana showed the same pattern, suggesting retail and institutional spot accumulation rather than derivative speculation.

Outliers and Options Sentiment

Hedera (HBAR) proved an exception, rising 13% since midnight and 14% over 24 hours to $0.11, marking the only CoinDesk 100 constituent gaining more than 3% on the day. The token’s run appeared technical rather than news-driven, though IBM’s inclusion of The Hashgraph Group’s IDTrust identity platform on its cloud catalog on Sept. 23 may have provided underlying support.

Options positioning offered mixed signals. On Deribit, the $84,000 Bitcoin put option expiring Sept. 30 was the most heavily traded contract, suggesting hedging demand against further declines. For Ethereum, the $2,850 call expiring Oct. 20 led activity, indicating some traders still positioned for upside moves.

Bitcoin Cash (BCH) continued unwinding its recent CME-driven surge, falling 7.7% to $306.69 and 10% over 24 hours. A handful of older layer-1 tokens held up better — Algorand (ALGO) rose 2.3%, as did XDC Network, while IOTA and Just token posted modest gains.

Volatility remained historically subdued. Volmex’s BVIV, the 30-day implied volatility index for Bitcoin, rose slightly to 37.4%, still near the sub-36% floor tested last week. Traditional markets’ VIX ticked up to 16 on Friday from under 14, signaling modest concern rather than panic.

Despite Monday’s reversal, CoinMarketCap’s altcoin season index remained at 65/100, its highest level in more than three months. The metric suggests that even with the day’s unwind, smaller tokens maintain structural outperformance relative to Bitcoin — though the durability of that advantage hinges on whether geopolitical oil tensions ease or escalate.