How does SPX trade on days 0DTE implied volatility opens at 20% or higher?

SPX sessions with 0DTE IV 20% and above at the open · 118 sessions · the archive filtered by the dealer book · all sessions · the calendar

Short answer. 118 of 1,103 archived SPX sessions matched. Of them 64% closed above the zero-gamma flip (archive 84%), 24% held the expected-hold band (archive 60%) and the mean open-to-close move was 1.23% (archive 0.60%). Counts over finished sessions, recomputed as the archive grows; a share equal to the archive's is a base rate, not a pattern.

118 of 1,103 sessions match. Of them 64% closed above the flip (archive 84%), 24% held the expected-hold band (archive 60%), mean open-to-close move 1.23% (archive 0.60%).

Every row is a finished SPX session and links to its page, where the same numbers stand with the day's events and a free minute-by-minute replay. The filters are the closing measurements those pages print: the zero-gamma flip against the close and the open, the net-gamma percentile, how often the flip was crossed, whether the expected-hold band held, and the calendar event the day carried. The shares above are counts over the matched days next to the same counts over the whole archive; a share that matches the archive is a base rate, not a pattern.

SessionCloseMoveFlipvs flipPctlCrossBandEvents
2025-11-216,602.80+0.46%6,522.7+80.1930brokeFed, Opex
2025-04-305,563.40+1.58%5,349.5+213.91000heldPCE, GDP, Refunding, VIX settlement, EIA
2025-04-255,525.34+0.71%5,384.6+140.71000heldRetail sales, UMich
2025-04-245,484.65+1.96%5,220.4+264.31000heldHousing, Claims, EIA, Auctions
2025-04-235,377.07-0.77%5,307.0+70.1940heldHousing, VIX settlement, EIA, Auctions, Fed
2025-04-225,287.57+1.51%5,140.3+147.3990heldAuctions
2025-04-215,159.90-1.34%5,114.3+45.61004broke
2025-04-175,282.85-0.33%5,161.1+121.8990heldHousing, Claims, EIA, Fed, Opex
2025-04-165,274.90-1.27%5,138.7+136.21000heldRetail sales, VIX settlement, EIA, Auctions, Fed
2025-04-145,405.10-0.87%5,227.5+177.61000held
2025-04-115,360.72+1.90%5,182.1+178.6370heldPPI, UMich
2025-04-105,268.22-1.47%5,234.2+34.0682brokeCPI, Claims, EIA, Auctions
2025-04-095,454.52+10.00%5,453.0+1.5833brokeVIX settlement, EIA, Auctions
2025-04-084,987.15-4.77%5,026.0-38.9117brokeAuctions
2025-04-075,063.06+3.30%5,035.1+28.08314brokeHalts
2025-04-045,074.67-3.70%5,076.0-1.3833brokeNFP, Fed
2025-03-315,611.40+1.61%5,597.2+14.2921broke
2025-03-125,600.19-0.49%5,609.6-9.401brokeCPI, VIX settlement, EIA, Auctions
2025-03-115,572.65-0.60%5,400.4+172.3802heldJOLTS, Auctions
2025-03-105,614.39-1.34%5,534.3+80.1690held
2025-03-075,769.90+0.73%5,683.3+86.6730brokeNFP, Fed
2025-03-065,737.42-0.50%5,592.0+145.4740heldClaims, EIA
2025-03-055,841.37+1.00%5,627.9+213.5710heldHousing, VIX settlement, ISM, EIA, Fed
2025-03-045,778.45-0.48%5,575.4+203.105held
2024-09-185,618.30-0.34%5,589.0+29.3342heldHousing, VIX settlement, EIA, FOMC
2024-08-085,321.16+1.23%5,231.9+89.3131heldClaims, EIA, Auctions
2024-08-065,238.87+0.62%5,225.9+13.0846brokeAuctions
2024-08-055,187.74+1.20%5,080.9+106.8116brokeISM, Fed
2024-08-025,345.79-0.47%5,340.6+5.27810brokeNFP, Housing
2023-03-243,971.87+1.02%3,968.1+3.847brokeHousing, UMich
2023-03-223,936.62-1.62%3,906.4+30.2813brokeVIX settlement, EIA, FOMC
2023-03-203,950.82+0.61%3,886.2+64.610012held
2023-03-173,915.85-0.89%3,921.2-5.38910brokeOpex
2023-03-163,960.81+2.36%3,944.6+16.210010brokeHousing, Claims, EIA
2023-03-153,889.95+0.75%3,883.2+6.8619brokePPI, Retail sales, VIX settlement, EIA
2023-03-143,920.85+0.32%3,921.0-0.223brokeCPI
2023-03-133,856.47+0.85%3,828.9+27.6952brokeHalts
2023-03-103,861.60-1.16%3,863.4-1.813brokeNFP, UMich
2023-02-144,135.67+0.55%4,134.4+1.349brokeCPI, PPI
2023-02-014,117.72+1.30%4,116.5+1.27710brokeRefunding, VIX settlement, ISM, JOLTS, Housing, EIA, FOMC
2023-01-123,983.75+0.11%3,941.0+42.8910brokeCPI, Claims, EIA, Auctions
2023-01-063,894.32+1.50%3,983.6-89.3982brokeNFP, Housing
2022-12-163,852.14-0.42%3,788.7+63.4582brokeOpex
2022-12-143,997.90-0.60%3,841.3+156.6500brokeVIX settlement, EIA, FOMC
2022-12-134,020.22-1.97%4,027.2-7.03414brokeCPI, Auctions
2022-11-304,075.67+2.89%4,113.2-37.5111brokeGDP, VIX settlement, JOLTS, EIA, Fed, Opex
2022-11-113,993.00+0.80%4,028.4-35.4283brokeUMich
2022-11-103,954.42+1.62%3,954.5-0.18610brokeCPI, Claims, EIA, Auctions
2022-11-093,749.47-1.47%3,723.7+25.8864brokeVIX settlement, EIA, Auctions
2022-11-043,771.49-0.22%3,714.2+57.3908brokeNFP
2022-11-033,721.19+0.09%3,714.1+7.1990brokeHousing, Claims, ISM, EIA
2022-11-023,760.95-2.27%3,792.3-31.42113brokeRefunding, VIX settlement, EIA, FOMC
2022-10-313,871.72-0.10%3,855.8+15.9998heldRefunding
2022-10-263,830.19+0.09%3,841.2-11.01004brokeHousing, VIX settlement, EIA, Auctions
2022-10-243,798.55+0.85%3,679.4+119.2973broke
2022-10-213,753.64+2.73%3,755.3-1.7922brokeOpex
2022-10-203,665.52-0.73%3,662.8+2.7031brokeClaims, EIA
2022-10-193,696.65-0.22%3,695.0+1.7784brokeHousing, VIX settlement, EIA, Auctions
2022-10-183,720.90-1.04%3,680.6+40.37116broke
2022-10-173,678.40+0.56%3,584.2+94.2896held
2022-10-143,586.86-2.87%3,563.8+23.11123brokeRetail sales, UMich
2022-10-133,670.01+4.81%3,674.2-4.2014brokeCPI, Claims, EIA, Auctions
2022-10-123,578.17-0.20%3,490.6+87.6980heldPPI, VIX settlement, Auctions
2022-10-113,587.80-0.17%3,586.2+1.6748broke
2022-10-103,613.57-1.00%3,619.1-5.5117broke
2022-10-073,641.52-1.59%3,608.7+32.8980heldNFP
2022-10-053,780.25+0.84%3,782.9-2.703brokeVIX settlement, ISM, EIA
2022-10-033,678.02+1.47%3,632.1+45.91000brokeISM, Housing
2022-09-303,587.67-1.32%3,556.0+31.710024brokePCE
2022-09-293,640.87-1.14%3,638.4+2.5110brokeGDP, Claims, EIA
2022-09-283,719.20+1.76%3,713.3+5.910018brokeVIX settlement, Fed, EIA, Auctions
2022-09-273,646.87-1.24%3,640.5+6.4928brokeHousing, Confidence, Auctions
2022-09-263,656.12-0.70%3,662.9-6.8411broke
2022-09-233,693.67-0.62%3,672.5+21.21323brokeUMich
2022-09-223,758.69-0.79%3,790.7-32.0523brokeClaims, EIA
2022-09-213,790.82-2.29%3,805.7-14.9846brokeVIX settlement, EIA, FOMC
2022-09-193,899.47+1.57%3,901.1-1.6018broke
2022-09-163,874.41+0.45%3,890.0-15.6147brokeOpex
2022-08-264,058.52-3.35%4,090.8-32.317brokePCE, Fed, UMich
2022-07-274,022.37+1.65%4,028.2-5.8513brokeHousing, VIX settlement, EIA, FOMC
2022-07-143,789.32+0.98%3,798.2-8.9012heldPPI, Claims, EIA
2022-07-133,803.05+0.84%3,770.8+32.31004brokeCPI, VIX settlement, EIA, Auctions
2022-07-063,844.71+0.30%3,835.3+9.41003brokeVIX settlement, ISM, JOLTS
2022-07-053,831.12+1.66%3,828.2+2.99815brokeHousing
2022-07-013,822.85+0.97%3,761.8+61.010011brokeISM, Housing
2022-06-303,780.79+0.02%3,766.5+14.31000brokePCE, Claims, EIA
2022-06-293,818.81-0.17%3,790.6+28.21002heldGDP, Fed, VIX settlement, EIA
2022-06-233,796.97+0.38%3,794.4+2.6966brokeClaims, Fed, EIA
2022-06-223,760.65+1.10%3,772.4-11.81005brokeFed, VIX settlement, Auctions
2022-06-213,763.82+0.78%3,771.9-8.151held
2022-06-173,673.32-0.08%3,716.2-42.9011brokeFed, Opex
2022-06-163,665.62-0.99%3,727.6-62.091brokeHousing, Claims, EIA
2022-06-153,788.75+0.46%3,853.9-65.210018brokeRetail sales, VIX settlement, EIA, FOMC
2022-06-143,736.39-0.84%3,727.6+8.81007brokePPI
2022-06-133,751.84-1.38%3,779.6-27.813broke
2022-06-103,898.87-1.37%4,034.8-135.903heldCPI, UMich
2022-06-034,107.97-0.42%4,123.7-15.7266brokeNFP, ISM
2022-05-314,133.06-0.18%4,158.7-25.6248brokeConfidence, Opex
2022-05-264,058.55+1.67%3,981.7+76.91000heldGDP, Claims, EIA, Auctions, Fed
2022-05-253,978.00+1.23%3,976.3+1.7155brokeHousing, VIX settlement, EIA, Auctions
2022-05-243,940.41+0.19%3,941.2-0.89610brokeHousing, Fed
2022-05-233,973.02+1.01%3,974.2-1.26812broke
2022-05-203,903.52-0.79%3,850.7+52.810012brokeOpex
2022-05-193,901.97+0.21%3,893.4+8.6995brokeClaims, EIA
2022-05-183,924.20-2.87%3,961.3-37.14115brokeHousing, VIX settlement, EIA, Auctions
2022-05-164,007.44-0.06%3,990.6+16.813broke
2022-05-134,023.25+1.24%4,062.3-39.1267brokeHousing, UMich
2022-05-113,934.19-1.40%3,919.7+14.5977heldCPI, VIX settlement, EIA, Auctions
2022-05-104,001.87-1.59%3,989.0+12.99826broke
2022-05-093,991.46-1.74%3,944.6+46.99123heldFed
2022-05-064,125.09+0.08%4,115.3+9.8995brokeNFP
2022-05-044,300.15+2.88%4,302.9-2.7124brokeRefunding, VIX settlement, ISM, EIA, FOMC
2022-05-034,173.47+0.40%4,123.4+50.1886brokeHousing, JOLTS
2022-05-024,155.12+0.42%4,168.1-13.0203brokeISM, Housing, Refunding
2022-04-294,131.27-2.73%4,168.8-37.501brokePCE
2022-04-274,185.27-0.12%4,160.1+25.2983brokeVIX settlement, EIA, Auctions
2022-04-264,177.05-2.16%4,189.3-12.31413brokeHousing, Confidence
2022-04-254,296.66+1.28%4,315.2-18.5619brokeRetail sales

Turn a filter into a rule

A count is where a question starts. The Lab takes a rule in plain words ("sell the 0DTE straddle at 10:00 on days that opened below the flip with the percentile under 20"), compiles it against every archived session and reports the out-of-sample verdict with day-clustered intervals. An assistant with the MCP server can page through the same archive with list_sessions and get_session.

Measurements are model output derived from public trade and quote data; they are approximations and can be wrong. Nothing here is investment advice; see the Terms.