How often does SPX reclaim the zero-gamma flip after opening below it?

SPX sessions opened below the flip · 200 sessions · the archive filtered by the dealer book · all sessions · the calendar

Short answer. 200 of 1,103 archived SPX sessions matched. Of them 79% closed above the zero-gamma flip (archive 84%), 56% held the expected-hold band (archive 60%) and the mean open-to-close move was 0.70% (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.

200 of 1,103 sessions match. Of them 79% closed above the flip (archive 84%), 56% held the expected-hold band (archive 60%), mean open-to-close move 0.70% (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
2026-09-147,620.30+0.26%7,665.1-44.8882broke
2026-09-117,657.42-0.02%7,717.1-59.7272heldCPI, UMich, Fed
2026-09-097,636.30-0.22%7,692.7-56.4822heldVIX settlement, Auctions
2026-09-087,673.30-0.43%7,713.4-40.1220heldAuctions
2026-09-037,747.67+0.62%7,659.6+88.11001brokeClaims, ISM, EIA, Auctions
2026-09-027,666.27+0.39%7,705.5-39.202brokeHousing, VIX settlement, EIA, Fed
2026-09-017,631.02-0.00%7,579.9+51.1681heldISM, JOLTS, Housing
2026-08-287,711.72-0.32%7,811.4-99.7482brokeUMich
2026-08-277,731.45+0.36%7,654.1+77.3693brokeClaims, EIA, Auctions
2026-08-267,675.95+0.13%7,663.1+12.8993brokePCE, Housing, GDP, VIX settlement, EIA, Auctions
2026-08-247,653.24-0.03%7,604.6+48.6821held
2026-08-187,690.64-0.22%7,696.7-6.1323heldHousing, Auctions
2026-08-177,745.45-0.53%7,745.0+0.402broke
2026-07-307,437.15+0.79%7,407.7+29.41003brokePCE, GDP, Claims, EIA
2026-06-167,511.70-0.61%7,526.0-14.3815brokeHousing, Auctions
2026-06-047,585.25+0.68%7,476.7+108.61001heldClaims, Fed, EIA
2026-05-267,519.02+0.03%7,461.9+57.11001heldConfidence, Auctions
2026-05-157,407.72-0.30%7,328.6+79.1981heldOpex
2026-05-147,501.21+0.51%7,491.8+9.41007brokeRetail sales, Claims, EIA
2026-04-247,164.55+0.53%7,055.7+108.91001heldUMich
2026-03-166,699.55+0.12%6,583.5+116.1941held
2026-02-236,837.67-1.01%6,771.5+66.2641heldHousing
2026-02-206,909.09+1.06%6,805.7+103.41001heldPCE, GDP, UMich, Housing, Opex
2026-01-306,938.85-0.19%6,845.5+93.4891heldPPI
2026-01-266,950.70+0.37%6,881.4+69.3991heldHousing, Auctions
2026-01-226,912.90-0.12%6,837.0+75.9741heldPCE, GDP, Claims, EIA
2026-01-216,875.10+0.73%6,858.4+16.71007brokeVIX settlement, Housing, Auctions
2026-01-156,944.02-0.30%6,904.8+39.2923heldClaims, EIA
2026-01-146,927.60-0.14%6,857.2+70.4751heldPPI, Retail sales, VIX settlement, EIA, Fed
2026-01-126,977.82+0.57%6,911.4+66.4991heldAuctions
2026-01-076,921.37-0.33%6,903.3+18.1931heldHousing, VIX settlement, JOLTS, EIA
2026-01-026,858.32-0.40%6,786.7+71.6961heldISM, EIA
2025-12-296,905.56+0.02%6,856.3+49.31001held
2025-12-226,878.40+0.18%6,821.4+57.01001heldAuctions
2025-12-176,722.06-1.21%6,697.9+24.21001heldVIX settlement, EIA, Auctions
2025-12-116,900.94+0.63%6,811.1+89.81001heldClaims, EIA, Auctions
2025-12-106,886.21+0.73%6,827.2+59.0961brokeVIX settlement, EIA, FOMC
2025-12-056,870.36-0.03%6,806.9+63.51001heldPCE
2025-11-136,737.27-1.20%6,690.3+47.0901heldEIA, Auctions
2025-11-076,728.72+0.64%6,599.3+129.4935held
2025-11-036,851.32-0.32%6,771.9+79.4971heldISM, Fed, Refunding
2025-10-026,715.97-0.12%6,641.0+75.0991heldEIA
2025-09-296,661.52-0.09%6,628.5+33.0971held
2025-08-286,502.27+0.16%6,414.6+87.71001heldGDP, Claims, EIA, Auctions
2025-06-135,976.75-0.39%5,870.1+106.6921heldUMich, Fed
2025-04-095,454.52+10.00%5,453.0+1.5833brokeVIX settlement, EIA, Auctions
2025-04-045,074.67-3.70%5,076.0-1.3833brokeNFP, Fed
2025-04-025,672.04+1.79%5,530.2+141.81001heldHousing, VIX settlement, EIA
2025-03-315,611.40+1.61%5,597.2+14.2921broke
2025-03-285,579.60-1.72%5,547.2+32.41001brokePCE, UMich
2025-03-195,675.42+0.73%5,682.0-6.69229brokeEIA, FOMC
2025-03-035,849.17-2.04%5,819.7+29.504brokeISM, Housing
2025-02-245,984.55-0.84%5,976.8+7.8971heldAuctions
2025-02-066,082.67+0.14%6,011.2+71.5971heldClaims, EIA
2025-01-296,038.10-0.31%6,011.2+26.9809heldVIX settlement, EIA, FOMC
2025-01-276,012.80+0.47%5,908.0+104.8811heldHousing, Auctions
2024-12-246,037.27+0.92%6,026.6+10.742brokeVIX settlement, Auctions
2024-12-205,933.15+1.63%5,921.5+11.67717brokePCE, Opex
2024-12-166,073.85+0.11%6,027.4+46.51001held
2024-12-136,050.30-0.35%6,015.4+34.91001heldUMich
2024-12-096,053.07-0.48%6,039.6+13.5901held
2024-11-275,997.97-0.24%5,960.4+37.6981heldPCE, Housing, GDP, Claims, VIX settlement, EIA, Auctions
2024-11-266,021.37+0.34%5,957.0+64.41001heldHousing, Confidence, Auctions
2024-11-225,969.55+0.28%5,936.2+33.41001heldUMich
2024-11-215,948.87+0.15%5,857.6+91.3971heldClaims, EIA
2024-11-195,916.82+0.95%5,882.2+34.6891brokeHousing
2024-11-055,782.72+0.96%5,716.2+66.5489heldISM, Auctions
2024-10-305,816.10-0.20%5,801.4+14.7989heldGDP, Refunding, VIX settlement, EIA
2024-10-285,824.36-0.21%5,795.2+29.21001heldAuctions, Refunding
2024-10-245,809.82-0.06%5,753.3+56.5991heldHousing, Claims, EIA
2024-10-225,851.67+0.41%5,784.0+67.71001held
2024-10-165,842.72+0.47%5,772.4+70.3901heldVIX settlement
2024-10-105,780.35+0.11%5,723.2+57.21001heldCPI, Claims, EIA, Auctions
2024-09-265,746.17-0.25%5,717.8+28.41001heldHousing, GDP, Claims, EIA, Auctions
2024-09-165,632.35+0.15%5,582.9+49.51001held
2024-09-125,594.92+0.76%5,523.4+71.5931heldPPI, Claims, EIA, Fed, Auctions
2024-09-115,554.32+1.29%5,616.0-61.702brokeCPI, VIX settlement, EIA, Auctions
2024-09-065,409.24-1.94%5,364.8+44.49137brokeNFP
2024-09-045,520.47+0.15%5,473.2+47.3881heldHousing, VIX settlement, JOLTS
2024-09-035,527.82-1.55%5,512.5+15.3991brokeISM, Housing
2024-08-265,616.92-0.49%5,586.9+30.0971heldHousing
2024-08-125,343.62-0.26%5,293.4+50.2971held
2024-08-055,187.74+1.20%5,080.9+106.8116brokeISM, Fed
2024-07-315,522.19+0.37%5,513.7+8.5559brokeRefunding, VIX settlement, EIA, FOMC
2024-07-305,436.27-0.75%5,409.5+26.8909brokeConfidence, JOLTS
2024-07-295,464.52-0.13%5,427.2+37.3931heldRefunding
2024-07-265,459.37+0.47%5,409.8+49.6621brokePCE, UMich
2024-07-245,427.81-1.46%5,422.1+5.7873brokeHousing, VIX settlement, EIA, Auctions
2024-07-225,564.96+0.42%5,496.0+69.01001held
2024-07-185,545.79-0.97%5,642.3-96.506brokeClaims, EIA
2024-07-175,589.10-0.40%5,540.4+48.71001heldHousing, VIX settlement, EIA, Auctions
2024-07-125,611.87+0.30%5,545.7+66.2731heldPPI, UMich
2024-07-095,577.12-0.09%5,543.9+33.2623heldFed, Auctions
2024-07-055,567.10+0.55%5,505.3+61.8961heldNFP, EIA
2024-07-025,508.77+0.92%5,434.7+74.1491heldJOLTS
2024-06-255,470.15+0.20%5,428.2+41.91001heldConfidence
2024-06-215,467.02+0.06%5,421.6+45.4761heldOpex
2024-06-055,353.32+0.80%5,253.3+100.0801heldVIX settlement, ISM, EIA
2024-06-035,281.82-0.25%5,218.3+63.5951heldISM, Housing, Halts
2024-05-295,266.90-0.04%5,236.7+30.28913brokeVIX settlement, Auctions
2024-05-245,304.00+0.34%5,243.6+60.41001heldHousing, UMich
2024-05-235,267.81-1.26%5,241.0+26.8971heldHousing, Claims, EIA
2024-05-035,128.77+0.03%5,076.6+52.210015heldNFP, ISM
2024-05-015,020.27-0.22%5,008.0+12.39819brokeRefunding, VIX settlement, ISM, JOLTS, Housing, EIA, FOMC
2024-04-305,036.57-1.21%5,043.8-7.208brokeConfidence
2024-04-255,048.87+0.82%4,945.9+103.01003heldGDP, Claims, EIA, Auctions
2024-04-185,011.00-0.50%4,960.8+50.2791heldClaims, EIA
2024-04-155,061.25-1.99%5,067.1-5.904brokeRetail sales
2024-04-125,122.80-0.74%5,074.0+48.8861heldUMich
2024-04-105,161.75+0.23%5,094.2+67.6841heldCPI, VIX settlement, EIA, Auctions
2024-04-025,206.17+0.06%5,162.4+43.8971heldHousing, JOLTS
2024-03-215,242.55-0.17%5,218.5+24.1981heldClaims, EIA
2024-03-195,177.35+0.75%5,182.3-4.904brokeHousing, Auctions
2024-03-155,115.77-0.23%5,080.0+35.8971heldOpex
2024-03-145,151.45-0.43%5,113.2+38.3651heldPPI, Retail sales, Claims, Halts, EIA
2024-03-135,165.45-0.20%5,135.2+30.31001heldVIX settlement, EIA, Auctions
2024-03-125,175.49+0.65%5,098.4+77.11001heldCPI, Auctions
2024-03-085,124.37-0.73%5,134.1-9.7018brokeNFP, UMich
2024-01-264,890.10-0.05%4,853.7+36.41001heldPCE, UMich
2024-01-244,867.95-0.46%4,857.5+10.4961heldVIX settlement, EIA, Auctions
2024-01-174,739.26+0.12%4,694.5+44.81001heldRetail sales, VIX settlement, Auctions
2024-01-164,765.57-0.11%4,729.2+36.41001held
2024-01-094,755.17+0.41%4,706.9+48.31003heldAuctions
2024-01-084,763.77+1.28%4,679.1+84.7881held
2023-12-224,755.32-0.08%4,728.5+26.802heldPCE, Housing, UMich
2023-12-124,642.97+0.55%4,584.7+58.3861heldCPI, Auctions
2023-12-044,570.02+0.21%4,530.3+39.71001brokeHousing
2023-11-274,551.25-0.13%4,524.2+27.11001heldHousing, Auctions
2023-11-214,538.99+0.04%4,500.0+39.0971held
2023-11-134,411.12+0.17%4,383.0+28.11001held
2023-11-014,237.42+0.85%4,216.4+21.09511brokeRefunding, VIX settlement, ISM, JOLTS, Housing, EIA, FOMC
2023-10-204,223.91-1.07%4,193.9+30.01001heldOpex
2023-10-174,373.10+0.68%4,344.1+29.0981brokeRetail sales
2023-09-224,319.57-0.42%4,310.7+8.9971brokeUMich
2023-09-214,329.91-1.05%4,337.7-7.8210brokeClaims, EIA
2023-09-184,454.15+0.13%4,450.3+3.8981broke
2023-09-154,448.62-0.92%4,454.1-5.508brokeOpex
2023-09-144,505.61+0.38%4,455.7+49.91001heldPPI, Retail sales, Claims, EIA
2023-09-114,488.10+0.01%4,442.8+45.3651held
2023-09-084,458.17+0.06%4,432.2+26.0901heldUMich, Fed
2023-09-074,452.17+0.36%4,433.1+19.1951brokeClaims, EIA
2023-09-054,496.90-0.33%4,490.1+6.8835brokeHousing
2023-09-014,514.42-0.48%4,484.4+30.01001brokeNFP, ISM, Housing
2023-08-254,405.15+0.21%4,310.4+94.89213heldUMich
2023-06-304,450.05+0.51%4,391.7+58.432heldPCE
2023-06-214,365.75-0.17%4,332.8+32.9997brokeFed, VIX settlement, Auctions
2023-06-064,284.77+0.42%4,251.0+33.81001held
2023-06-024,281.02+0.65%4,214.2+66.81003heldNFP
2023-05-124,124.30-0.42%4,079.2+45.11001heldHousing, UMich
2023-04-254,072.09-1.15%4,072.2-0.11228brokeHousing, Confidence
2023-02-273,981.87-0.53%3,990.2-8.3933brokeHousing
2023-02-243,969.55+0.20%3,961.2+8.410035brokePCE, Housing, UMich
2023-02-084,119.07-0.61%4,081.5+37.6991heldVIX settlement, EIA, Auctions
2023-01-314,076.19+1.23%4,053.0+23.2995brokeConfidence
2023-01-244,017.17+0.49%3,939.9+77.31001heldHalts
2023-01-033,824.57-0.83%3,797.0+27.6328brokeISM, Housing
2022-12-283,783.65-1.19%3,777.0+6.71001brokeVIX settlement, Auctions
2022-12-073,934.77+0.00%3,912.1+22.782heldVIX settlement, EIA
2022-11-224,005.01+0.86%3,908.0+97.01001heldAuctions
2022-11-173,947.65+0.86%3,850.1+97.61001heldHousing, Claims, EIA
2022-11-153,991.67-0.71%4,003.5-11.8312brokePPI, Fed
2022-11-013,857.77-1.35%3,864.2-6.4024brokeISM, JOLTS, Housing
2022-10-253,858.97+1.43%3,868.1-9.1961brokeConfidence
2022-10-243,798.55+0.85%3,679.4+119.2973broke
2022-10-133,670.01+4.81%3,674.2-4.2014brokeCPI, Claims, EIA, Auctions
2022-10-063,743.92-0.68%3,671.0+72.9441brokeGDP, Claims, EIA
2022-09-293,640.87-1.14%3,638.4+2.5110brokeGDP, Claims, EIA
2022-09-193,899.47+1.57%3,901.1-1.6018broke
2022-09-084,005.42+1.50%3,929.4+76.0248heldClaims, Fed, EIA
2022-09-023,923.30-1.90%3,955.7-32.416brokeNFP, Housing
2022-08-194,230.02-0.63%4,227.2+2.81001brokeOpex
2022-08-164,306.22+0.41%4,237.1+69.14018heldHousing
2022-08-124,279.60+1.21%4,293.4-13.802brokeUMich
2022-08-094,121.89-0.31%4,125.8-3.902held
2022-07-223,962.12-1.02%3,967.1-5.0310brokeUMich
2022-07-183,830.77-1.65%3,861.8-31.0010broke
2022-07-153,862.20+0.50%3,858.0+4.29917brokeRetail sales, Opex
2022-07-143,789.32+0.98%3,798.2-8.9012heldPPI, Claims, EIA
2022-07-083,898.52+0.35%3,905.9-7.4520brokeNFP, UMich
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
2022-06-223,760.65+1.10%3,772.4-11.81005brokeFed, VIX settlement, Auctions
2022-06-143,736.39-0.84%3,727.6+8.81007brokePPI
2022-06-084,115.20-0.56%4,128.3-13.110017brokeVIX settlement, EIA, Auctions
2022-06-074,160.42+1.84%4,111.4+49.01003broke
2022-06-064,122.72-0.76%4,066.2+56.59721brokeFed
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
2022-05-193,901.97+0.21%3,893.4+8.6995brokeClaims, EIA
2022-05-183,924.20-2.87%3,961.3-37.14115brokeHousing, VIX settlement, EIA, Auctions
2022-05-174,088.22+0.45%4,098.2-10.012brokeRetail sales, Fed
2022-05-113,934.19-1.40%3,919.7+14.5977heldCPI, VIX settlement, EIA, Auctions
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
2022-04-274,185.27-0.12%4,160.1+25.2983brokeVIX settlement, EIA, Auctions
2022-04-254,296.66+1.28%4,315.2-18.5619brokeRetail sales
2022-04-184,391.07+0.00%4,435.2-44.1018broke
2019-06-192,929.35+0.29%2,933.3-4.010035brokeVIX settlement, EIA, FOMC

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.