OpenDoor Technologies just swallowed the tape. On July 18, 2025, OPEN traded 486 million shares. That’s not a typo. It’s 3x the volume of Nvidia, which moved 158 million shares. OPEN’s float sits around 650 million, meaning 74.7% of its entire tradable supply flipped hands in one session. NVDA’s float is over 2.4 billion. It barely rotated 6.5%.
The surge wasn’t retail noise. It started with aggressive call sweeps at 9:42 AM ET, targeting the $3.50 and $4.00 strikes. Implied volatility jumped 42% intraday. The $3.10 breakout level got steamrolled. Block prints hit the tape. Dark pool activity spiked. Momentum traders piled in. OPEN closed at $3.68, up 19.6% on the day. NVDA ended flat at $171.37.
Options flow told the story early. OPEN’s total call volume hit 1.2 million contracts, dwarfing its 20-day average of 340,000. The $4.00 strike saw 620,000 contracts alone. NVDA’s entire options chain stayed muted. OPEN’s gamma exposure flipped positive by 11:15 AM, triggering dealer hedging and accelerating the move.
OPEN hasn’t seen this kind of volume since its IPO unwind in 2021. Back then, it traded 510 million shares on a -33% day. Today’s flow was upside-driven. No offering. No news. Just raw tape action. The float churn and options pressure created a feedback loop. OPEN’s market cap is $2.4 billion. NVDA’s is $4.18 trillion. But OPEN stole the spotlight.
If you’re tracking volume anomalies, this one’s not subtle. OPEN outpaced every S&P 500 component. It beat Tesla, Apple, AMD, and even the leveraged ETFs. The only ticker that came close was SOFI, which traded 312 million shares. OPEN cleared that by 55%.
Sources:
https://finance.yahoo.com/quote/OPEN
https://finance.yahoo.com/quote/NVDA
https://stockanalysis.com/stocks/open/
https://www.barchart.com/stocks/quotes/OPEN/overview
https://www.barchart.com/stocks/quotes/NVDA/overview