How does SPX trade on days it closes in negative gamma?

SPX sessions closed in negative gamma · 177 sessions · the archive filtered by the dealer book · all sessions · the calendar

Short answer. 177 of 1,103 archived SPX sessions matched. Of them 7% held the expected-hold band (archive 60%) and the mean open-to-close move was 0.92% (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.

177 of 1,103 sessions match. Of them 0% closed above the flip (archive 84%), 7% held the expected-hold band (archive 60%), mean open-to-close move 0.92% (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
2026-09-157,585.17-0.33%7,664.3-79.11001heldAuctions
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
2026-09-107,591.67-0.03%7,644.0-52.301heldPPI, Claims, EIA, Auctions
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
2026-09-027,666.27+0.39%7,705.5-39.202brokeHousing, VIX settlement, EIA, Fed
2026-08-317,686.10-0.06%7,730.6-44.5771heldOpex
2026-08-287,711.72-0.32%7,811.4-99.7482brokeUMich
2026-08-187,690.64-0.22%7,696.7-6.1323heldHousing, Auctions
2026-08-057,712.99-0.94%7,720.7-7.707brokeRefunding, VIX settlement, ISM, EIA
2026-08-047,736.35+1.31%7,745.1-8.8288brokeHousing, JOLTS
2026-07-317,489.97+0.23%7,501.1-11.1025brokeUMich
2026-07-017,483.35+0.14%7,488.2-4.803brokeVIX settlement, ISM, Housing, EIA
2026-06-167,511.70-0.61%7,526.0-14.3815brokeHousing, Auctions
2026-05-297,581.22+0.11%7,584.8-3.621brokeOpex
2026-04-157,023.14+0.66%7,026.0-2.901brokeVIX settlement, EIA, Fed
2026-04-136,886.26+1.28%6,891.2-4.9816broke
2025-12-016,812.80+0.09%6,818.7-5.903brokeISM, Fed
2025-09-166,607.10-0.26%6,610.2-3.112brokeRetail sales, Auctions
2025-09-046,501.80+0.74%6,566.4-64.601brokeClaims, ISM, EIA
2025-05-065,607.32+0.15%5,630.3-23.0582brokeAuctions
2025-04-084,987.15-4.77%5,026.0-38.9117brokeAuctions
2025-04-045,074.67-3.70%5,076.0-1.3833brokeNFP, Fed
2025-04-015,632.60+0.78%5,634.1-1.513brokeISM, JOLTS, Housing
2025-03-275,692.62-0.05%5,712.4-19.8994brokeGDP, Claims, EIA, Auctions
2025-03-205,662.02+0.48%5,663.3-1.37416brokeClaims, EIA
2025-03-195,675.42+0.73%5,682.0-6.69229brokeEIA, FOMC
2025-03-125,600.19-0.49%5,609.6-9.401brokeCPI, VIX settlement, EIA, Auctions
2025-02-285,952.72+1.50%6,305.7-353.001brokePCE, UMich, Opex
2024-12-185,872.81-2.88%5,971.1-98.305brokeHousing, VIX settlement, EIA, FOMC
2024-09-115,554.32+1.29%5,616.0-61.702brokeCPI, VIX settlement, EIA, Auctions
2024-08-075,200.16-1.89%5,221.8-21.68110brokeVIX settlement, EIA, Auctions
2024-07-185,545.79-0.97%5,642.3-96.506brokeClaims, EIA
2024-07-035,534.72+0.42%5,542.0-7.332brokeHousing, Claims, VIX settlement, ISM, EIA
2024-06-125,420.71+0.02%5,421.1-0.4610brokeCPI, VIX settlement, EIA, FOMC
2024-04-305,036.57-1.21%5,043.8-7.208brokeConfidence
2024-04-155,061.25-1.99%5,067.1-5.904brokeRetail sales
2024-04-045,148.32-1.98%5,166.1-17.8554brokeClaims, EIA
2024-03-195,177.35+0.75%5,182.3-4.904brokeHousing, Auctions
2024-03-085,124.37-0.73%5,134.1-9.7018brokeNFP, UMich
2024-02-134,952.15-0.07%4,992.9-40.803brokeCPI
2023-12-204,699.15-1.25%4,772.0-72.801brokeVIX settlement, EIA, Auctions
2023-10-264,136.60-0.95%4,153.9-17.38228brokeHousing, GDP, Claims, EIA, Auctions
2023-10-194,278.11-1.04%4,287.6-9.535brokeClaims, EIA
2023-09-284,298.86+0.73%4,327.6-28.797brokeGDP, Claims, EIA, Auctions
2023-09-214,329.91-1.05%4,337.7-7.8210brokeClaims, EIA
2023-09-204,401.82-1.15%4,409.4-7.67510brokeVIX settlement, EIA, FOMC
2023-09-154,448.62-0.92%4,454.1-5.508brokeOpex
2023-08-244,376.61-1.71%4,384.5-7.9629brokeHousing, Claims, EIA
2023-08-214,400.05+0.43%4,405.7-5.601broke
2023-08-164,404.85-0.68%4,433.7-28.89922brokeHousing, VIX settlement, EIA
2023-08-114,463.11+0.36%4,469.6-6.521brokePPI, UMich
2023-08-104,469.11-0.52%4,472.8-3.787brokeCPI, Claims, EIA, Auctions
2023-08-044,477.02-0.88%4,481.2-4.2011brokeNFP
2023-08-034,501.19+0.13%4,509.6-8.4982brokeHousing, Claims, ISM, EIA
2023-08-014,576.87+0.05%4,582.7-5.879brokeISM, JOLTS, Housing
2023-07-284,581.45+0.20%4,587.4-5.9192brokePCE, UMich
2023-07-274,538.94-1.33%4,539.7-0.83712brokeHousing, GDP, Claims, EIA, Auctions
2023-07-254,567.82+0.33%4,574.0-6.2143brokeConfidence, Auctions
2023-07-244,554.77+0.08%4,559.0-4.201broke
2023-07-064,412.17+0.06%4,412.3-0.1215brokeClaims, ISM, JOLTS, EIA
2023-07-054,446.82+0.22%4,453.0-6.257brokeHousing, VIX settlement, EIA
2023-06-284,377.60+0.24%4,384.8-7.215brokeVIX settlement, EIA, Auctions, Fed
2023-06-234,348.00+0.04%4,362.1-14.17516brokeUMich, Opex
2023-06-164,409.32-0.78%4,409.9-0.6920brokeOpex
2023-06-014,220.32+0.93%4,302.3-82.003brokeClaims, ISM, Housing, EIA
2023-05-264,205.21+1.10%4,211.3-6.147brokePCE, Housing, UMich
2023-05-254,151.32+0.18%4,162.7-11.4938brokeGDP, Claims, EIA, Auctions
2023-05-244,115.62-0.28%4,135.1-19.511brokeVIX settlement, EIA, Auctions
2023-05-184,198.80+1.05%4,261.6-62.825brokeClaims, EIA
2023-05-174,158.57+0.71%4,178.7-20.101brokeHousing, VIX settlement, EIA, Auctions
2023-05-044,060.30-0.48%4,079.3-19.09934brokeClaims, EIA
2023-05-024,119.11-0.88%4,126.1-7.0213brokeHousing, JOLTS
2023-04-264,057.32-0.58%4,068.7-11.411brokeHousing, VIX settlement, EIA, Auctions
2023-04-254,072.09-1.15%4,072.2-0.11228brokeHousing, Confidence
2023-04-204,129.42+0.10%4,135.2-5.8994brokeClaims, EIA
2023-04-134,146.20+1.03%4,149.9-3.701brokePPI, Claims, EIA, Auctions
2023-04-114,108.77-0.07%4,109.0-0.21008broke
2023-04-064,104.22+0.57%4,105.8-1.627brokeClaims, EIA
2023-03-304,050.82-0.05%4,054.5-3.701brokeGDP, Claims, EIA
2023-03-294,027.37+0.42%4,035.1-7.7404brokeVIX settlement, EIA, Auctions
2023-03-214,000.74+0.23%4,003.2-2.59526brokeAuctions
2023-03-173,915.85-0.89%3,921.2-5.38910brokeOpex
2023-03-143,920.85+0.32%3,921.0-0.223brokeCPI
2023-03-103,861.60-1.16%3,863.4-1.813brokeNFP, UMich
2023-03-093,917.82-2.06%3,950.9-33.101brokeClaims, EIA, Fed, Auctions
2023-03-034,045.96+1.24%4,048.0-2.051brokeISM
2023-02-273,981.87-0.53%3,990.2-8.3933brokeHousing
2023-02-234,012.80-0.20%4,014.8-2.069brokeGDP, Claims, EIA, Auctions
2023-02-174,078.72+0.28%4,079.8-1.1326brokeOpex
2023-02-164,092.07-0.21%4,100.6-8.5468brokeHousing, PPI, Claims, EIA
2023-02-094,081.49-1.74%4,089.5-8.029brokeClaims, EIA, Auctions, Fed
2023-02-074,165.82+1.61%4,171.1-5.3011broke
2023-01-264,060.85+0.33%4,078.6-17.8704brokeHousing, GDP, Claims, EIA, Auctions
2023-01-183,927.50-1.98%3,940.2-12.735brokePPI, Retail sales, VIX settlement, Auctions
2023-01-063,894.32+1.50%3,983.6-89.3982brokeNFP, Housing
2022-12-303,838.27+0.39%3,840.0-1.715broke
2022-12-273,828.47-0.40%3,829.8-1.337brokeConfidence
2022-12-134,020.22-1.97%4,027.2-7.03414brokeCPI, Auctions
2022-12-093,933.92-0.49%3,934.1-0.2272brokePPI, UMich, Fed
2022-12-024,071.20+0.95%4,079.6-8.405brokeNFP
2022-11-304,075.67+2.89%4,113.2-37.5111brokeGDP, VIX settlement, JOLTS, EIA, Fed, Opex
2022-11-254,027.02+0.04%4,030.5-3.5159brokeUMich, EIA
2022-11-153,991.67-0.71%4,003.5-11.8312brokePPI, Fed
2022-11-143,957.77-0.44%3,969.8-12.0161broke
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
2022-11-073,807.45+0.48%3,821.1-13.703brokeFed
2022-11-023,760.95-2.27%3,792.3-31.42113brokeRefunding, VIX settlement, EIA, FOMC
2022-11-013,857.77-1.35%3,864.2-6.4024brokeISM, JOLTS, Housing
2022-10-273,808.69-0.99%3,818.5-9.8017brokeHousing, GDP, Claims, EIA, Auctions
2022-10-263,830.19+0.09%3,841.2-11.01004brokeHousing, VIX settlement, EIA, Auctions
2022-10-253,858.97+1.43%3,868.1-9.1961brokeConfidence
2022-10-213,753.64+2.73%3,755.3-1.7922brokeOpex
2022-10-133,670.01+4.81%3,674.2-4.2014brokeCPI, Claims, EIA, Auctions
2022-10-103,613.57-1.00%3,619.1-5.5117broke
2022-10-053,780.25+0.84%3,782.9-2.703brokeVIX settlement, ISM, EIA
2022-09-263,656.12-0.70%3,662.9-6.8411broke
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
2022-09-153,902.26-0.71%3,932.5-30.25020brokeRetail sales, Claims, EIA
2022-09-143,947.10+0.10%3,960.9-13.803brokePPI, VIX settlement, EIA
2022-09-133,931.77-2.27%3,956.7-24.9011brokeCPI, Auctions
2022-09-094,067.94+0.90%4,075.7-7.873brokeUMich, Fed
2022-09-073,979.57+1.90%3,986.0-6.407brokeVIX settlement
2022-09-023,923.30-1.90%3,955.7-32.416brokeNFP, Housing
2022-08-264,058.52-3.35%4,090.8-32.317brokePCE, Fed, UMich
2022-08-244,140.40+0.32%4,145.2-4.805brokeHousing, VIX settlement, EIA, Auctions
2022-08-234,129.42-0.19%4,132.5-3.187brokeHousing
2022-08-184,283.35+0.17%4,284.7-1.3617brokeClaims, EIA
2022-08-154,297.02+0.89%4,307.1-10.1974broke
2022-08-124,279.60+1.21%4,293.4-13.802brokeUMich
2022-08-114,205.50-0.75%4,228.6-23.101brokePPI, Claims, EIA, Auctions
2022-08-094,121.89-0.31%4,125.8-3.902held
2022-08-084,140.82-0.54%4,143.8-3.009broke
2022-08-034,155.25+0.97%4,168.6-13.447heldHousing, Refunding, VIX settlement, ISM, EIA
2022-08-024,093.17-0.18%4,112.3-19.19816brokeJOLTS
2022-08-014,120.02+0.36%4,172.5-52.563brokeISM, Housing, Fed, Refunding
2022-07-274,022.37+1.65%4,028.2-5.8513brokeHousing, VIX settlement, EIA, FOMC
2022-07-263,921.47-0.72%3,928.0-6.521heldHousing, Confidence, Auctions
2022-07-253,967.75-0.03%3,982.5-14.8229broke
2022-07-223,962.12-1.02%3,967.1-5.0310brokeUMich
2022-07-203,959.29+0.69%3,966.7-7.4019brokeVIX settlement, EIA, Auctions
2022-07-183,830.77-1.65%3,861.8-31.0010broke
2022-07-143,789.32+0.98%3,798.2-8.9012heldPPI, Claims, EIA
2022-07-123,819.22-0.89%3,846.5-27.37610brokeAuctions
2022-07-083,898.52+0.35%3,905.9-7.4520brokeNFP, UMich
2022-07-073,903.32+0.86%3,904.6-1.3103brokeClaims, EIA
2022-06-283,822.21-2.57%3,851.4-29.211brokeConfidence, Auctions
2022-06-273,898.57-0.70%3,915.1-16.5713brokeHousing, Auctions
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
2022-06-133,751.84-1.38%3,779.6-27.813broke
2022-06-103,898.87-1.37%4,034.8-135.903heldCPI, UMich
2022-06-094,017.54-1.96%4,090.9-73.49926brokeClaims, EIA, Fed, Auctions
2022-06-084,115.20-0.56%4,128.3-13.110017brokeVIX settlement, EIA, Auctions
2022-06-034,107.97-0.42%4,123.7-15.7266brokeNFP, ISM
2022-06-014,101.00-1.39%4,130.3-29.39910brokeVIX settlement, ISM, JOLTS, Housing
2022-05-314,133.06-0.18%4,158.7-25.6248brokeConfidence, Opex
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
2022-05-183,924.20-2.87%3,961.3-37.14115brokeHousing, VIX settlement, EIA, Auctions
2022-05-174,088.22+0.45%4,098.2-10.012brokeRetail sales, Fed
2022-05-134,023.25+1.24%4,062.3-39.1267brokeHousing, UMich
2022-05-044,300.15+2.88%4,302.9-2.7124brokeRefunding, VIX settlement, ISM, EIA, FOMC
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
2022-04-264,177.05-2.16%4,189.3-12.31413brokeHousing, Confidence
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.