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

SPX sessions opened below the flip · 387 sessions · the archive filtered by the dealer book · all sessions · the calendar

Short answer. 387 of 1,121 archived SPX sessions matched. Of them 51% closed above the zero-gamma flip (archive 55%) and the mean open-to-close move was 0.64% (archive 0.59%). Counts over finished sessions, recomputed as the archive grows; a share equal to the archive's is a base rate, not a pattern.

387 of 1,121 sessions match. Of them 51% closed above the flip (archive 55%) and the mean open-to-close move was 0.64% (archive 0.59%).

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, 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 flipPctlCrossEvents
2026-10-087,764.20-0.12%7,765.0-0.821Claims, EIA, Auctions
2026-10-027,722.25-0.10%7,722.3-0.17015NFP, Housing
2026-10-017,666.87-0.02%7,658.0+8.8709Claims, ISM, Housing, EIA, Auctions
2026-09-297,669.87-0.27%7,668.6+1.3522Confidence, JOLTS, Auctions
2026-09-287,683.49-0.30%7,693.7-10.22514Retail sales
2026-09-247,704.75+0.46%7,693.4+11.41005Housing, Claims, EIA, Auctions
2026-09-237,705.12-0.65%7,716.5-11.302VIX settlement, EIA, Auctions
2026-09-157,584.55-0.34%7,586.0-1.4805Auctions
2026-09-147,620.56+0.27%7,626.6-6.1356
2026-09-107,591.60-0.02%7,597.6-6.04014PPI, Claims, EIA, Auctions
2026-09-027,666.21+0.40%7,666.0+0.24516Housing, VIX settlement, EIA, Fed
2026-09-017,630.64-0.01%7,639.0-8.3108ISM, JOLTS, Housing
2026-08-267,675.54+0.12%7,674.8+0.71018PCE, Housing, GDP, VIX settlement, EIA, Auctions
2026-08-257,677.27-0.03%7,669.0+8.39523Housing, Confidence, Auctions
2026-08-247,653.24-0.03%7,657.1-3.84512
2026-08-217,673.55+0.02%7,676.7-3.15034Opex
2026-08-197,706.75-0.22%7,718.9-12.21522VIX settlement, EIA, Auctions
2026-08-187,690.64-0.22%7,703.7-13.11530Housing, Auctions
2026-08-177,745.45-0.53%7,767.5-22.1010
2026-08-127,748.52-0.17%7,750.6-2.03522CPI, VIX settlement, EIA, Auctions
2026-07-237,407.80-0.12%7,404.4+3.45013Claims, EIA
2026-07-177,458.16+0.12%7,471.9-13.82510Housing, UMich, Opex
2026-07-097,542.75+0.69%7,528.3+14.4455Claims, EIA, Auctions
2026-07-087,482.92+0.34%7,466.2+16.7909VIX settlement, EIA, Auctions
2026-06-297,440.62+0.69%7,414.4+26.2955
2026-06-267,339.17+0.36%7,361.2-22.01020UMich, Opex
2026-06-247,358.75-0.22%7,374.9-16.2458Housing, VIX settlement, EIA, Auctions, Fed
2026-06-237,365.75+0.13%7,388.9-23.154Auctions
2026-06-127,431.79+0.32%7,421.0+10.86519UMich
2026-06-057,384.59-1.98%7,465.8-81.2152NFP
2026-06-047,585.25+0.68%7,571.1+14.1406Claims, Fed, EIA
2026-06-017,599.70+0.45%7,585.6+14.19519ISM, Housing
2026-05-297,581.22+0.11%7,580.9+0.44024Opex
2026-05-287,563.45+0.59%7,556.1+7.4605PCE, Housing, GDP, Claims, EIA, Auctions
2026-05-277,520.30-0.09%7,517.8+2.51036VIX settlement, Auctions
2026-05-267,519.02+0.03%7,513.4+5.68517Confidence, Auctions
2026-05-217,445.56+0.62%7,423.2+22.48519Housing, Claims, EIA
2026-05-207,432.50+0.79%7,409.2+23.3707EIA, Auctions
2026-05-197,354.17-0.17%7,364.8-10.72022VIX settlement
2026-05-157,407.72-0.30%7,429.9-22.12016Opex
2026-05-137,444.67+0.61%7,414.5+30.154PPI, VIX settlement, EIA, Auctions
2026-05-127,400.75+0.18%7,372.9+27.9857CPI, Auctions
2026-05-117,412.04+0.29%7,411.9+0.1453Auctions
2026-05-047,200.92-0.26%7,205.3-4.454Housing, Fed
2026-04-307,209.79+0.69%7,174.7+35.1205PCE, GDP, Claims, EIA
2026-04-297,136.05+0.11%7,128.3+7.76513Housing, Refunding, VIX settlement, EIA, FOMC
2026-04-287,138.45+0.07%7,133.7+4.72513Confidence, Auctions
2026-04-247,164.55+0.53%7,149.3+15.39511UMich
2026-04-177,125.72+0.57%7,120.8+4.9657Opex
2026-04-076,617.42+0.42%6,573.9+43.6805Housing, Auctions
2026-04-026,582.42+1.39%6,562.2+20.2857Claims, EIA
2026-03-276,369.70-1.16%6,409.8-40.108UMich
2026-03-266,477.72-0.97%6,521.3-43.6304Claims, EIA, Auctions
2026-03-246,556.00+0.24%6,567.2-11.23524Auctions
2026-03-206,506.42-1.18%6,534.8-28.43518Opex
2026-03-196,606.92+0.61%6,591.7+15.26545Housing, Claims, EIA, Fed
2026-03-186,624.85-0.98%6,661.4-36.51010Housing, PPI, VIX settlement, EIA, FOMC
2026-03-126,673.29-0.66%6,694.2-20.93026Housing, Claims, EIA, Auctions
2026-03-066,739.82-0.02%6,752.2-12.4518NFP, Retail sales
2026-03-036,816.60+0.60%6,801.7+15.0601VIX settlement
2026-02-266,908.31-0.45%6,897.1+11.2755Claims, Fed, EIA, Auctions
2026-02-246,890.15+0.83%6,882.8+7.4454Confidence, Auctions
2026-02-186,880.55+0.46%6,888.1-7.6759Housing, VIX settlement, Auctions
2026-02-136,836.35+0.01%6,852.3-15.94018CPI
2026-02-056,799.37-0.34%6,813.2-13.83014Claims, JOLTS, EIA
2026-01-276,978.77+0.21%6,979.9-1.1308Housing, Confidence, Auctions
2026-01-086,921.92+0.13%6,918.0+3.96329Claims, EIA
2025-12-306,895.89-0.13%6,902.7-6.81122Confidence
2025-12-296,905.56+0.02%6,902.9+2.77219
2025-12-176,722.06-1.21%6,750.0-27.91112VIX settlement, EIA, Auctions
2025-12-116,900.94+0.63%6,878.9+22.01009Claims, EIA, Auctions
2025-12-016,812.80+0.09%6,823.4-10.6510ISM, Fed
2025-11-286,848.69+0.04%6,832.4+16.31001UMich, EIA, Opex
2025-11-256,766.32+1.03%6,737.6+28.81007PPI, Retail sales, Confidence, Auctions
2025-11-196,642.05+0.31%6,637.2+4.9759VIX settlement, EIA, Auctions
2025-11-186,617.56-0.33%6,637.1-19.64520Housing
2025-11-176,672.66-0.52%6,698.4-25.74014Housing
2025-11-146,733.27+0.99%6,746.0-12.73014UMich
2025-11-136,737.27-1.20%6,768.1-30.8254EIA, Auctions
2025-11-076,728.72+0.64%6,684.0+44.8907
2025-11-066,719.47-0.98%6,745.4-25.9012EIA
2025-11-056,796.75+0.35%6,812.5-15.8252Refunding, VIX settlement, ISM, EIA
2025-11-046,771.87-0.17%6,786.8-14.9510
2025-10-306,823.12-0.47%6,854.3-31.21524EIA
2025-10-296,891.10-0.18%6,890.3+0.85514VIX settlement, EIA, FOMC
2025-10-226,699.45-0.50%6,699.0+0.45521VIX settlement, EIA, Auctions
2025-10-176,663.37+0.78%6,650.3+13.04515Opex
2025-10-146,645.20+0.83%6,644.5+0.7306Fed
2025-09-266,643.40+0.41%6,632.0+11.46017PCE, UMich
2025-09-256,604.25+0.08%6,599.2+5.17031Housing, GDP, Claims, EIA, Auctions
2025-09-196,664.50+0.30%6,650.3+14.3909Opex
2025-09-186,631.82+0.15%6,635.4-3.52522Claims, EIA
2025-09-026,415.17+0.60%6,389.6+25.6905ISM, Housing
2025-08-266,466.07+0.50%6,445.3+20.76019Housing, Confidence, Auctions
2025-08-216,369.95+0.05%6,371.7-1.83038Claims, EIA
2025-08-206,395.92-0.15%6,381.4+14.55513VIX settlement, EIA, Auctions
2025-08-146,469.50+0.41%6,459.5+10.0757PPI, Claims, EIA
2025-08-066,344.97+0.63%6,335.0+10.0857VIX settlement, EIA, Auctions
2025-08-056,299.50-0.51%6,309.3-9.808ISM, Auctions
2025-08-016,238.35-0.55%6,241.8-3.53711NFP, ISM, Housing
2025-07-316,341.46-1.01%6,385.0-43.5012PCE, Claims, EIA
2025-07-306,362.67-0.20%6,368.9-6.22112GDP, Refunding, VIX settlement, EIA, FOMC
2025-07-236,357.87+0.44%6,333.8+24.1477VIX settlement, EIA, Auctions
2025-07-226,310.50+0.07%6,302.6+7.99525Fed
2025-07-156,244.07-0.85%6,261.2-17.2518CPI
2025-06-236,025.42+0.98%5,992.1+33.310013
2025-06-126,044.70+0.55%6,035.2+9.51007PPI, Claims, EIA, Fed, Auctions
2025-06-116,022.71-0.40%6,035.1-12.44012CPI, VIX settlement, EIA, Auctions
2025-05-305,909.25+0.27%5,886.8+22.58019PCE, Opex
2025-05-235,802.87+0.50%5,809.9-7.03514Housing, UMich
2025-05-165,958.37+0.64%5,932.1+26.3953Housing, Opex
2025-05-155,915.25+0.76%5,900.6+14.6907PPI, Retail sales, Claims, Fed, EIA
2025-05-075,631.07+0.31%5,613.0+18.17535VIX settlement, EIA, FOMC
2025-05-065,607.32+0.15%5,618.0-10.71016Auctions
2025-04-105,268.22-1.47%5,254.3+13.94523CPI, Claims, EIA, Auctions
2025-04-075,063.06+3.30%5,036.6+26.55023Halts
2025-04-045,074.67-3.70%5,158.6-83.9100NFP, Fed
2025-04-025,672.04+1.79%5,645.9+26.1609Housing, VIX settlement, EIA
2025-03-315,611.40+1.61%5,564.9+46.5805
2025-03-285,579.60-1.72%5,600.0-20.402PCE, UMich
2025-03-275,692.62-0.05%5,707.0-14.4024GDP, Claims, EIA, Auctions
2025-03-205,662.02+0.48%5,668.6-6.6508Claims, EIA
2025-03-185,614.57-0.60%5,616.3-1.72036Housing, VIX settlement, Auctions
2025-03-135,521.45-1.11%5,542.5-21.03012PPI, Claims, EIA, Fed, Auctions
2025-03-105,614.39-1.34%5,629.6-15.2402
2025-03-075,769.90+0.73%5,742.0+27.95013NFP, Fed
2025-03-065,737.42-0.50%5,750.9-13.5406Claims, EIA
2025-03-045,778.45-0.48%5,797.6-19.23516
2025-02-285,952.72+1.50%5,879.2+73.57013PCE, UMich, Opex
2025-02-265,956.42-0.15%5,969.4-13.0405Housing, VIX settlement, EIA, Auctions
2025-02-216,013.52-1.60%6,059.4-45.806Opex
2025-02-186,128.22+0.08%6,113.2+15.09031
2025-02-126,051.72+0.75%6,042.9+8.85011CPI, VIX settlement, Fed, EIA, Auctions
2025-02-106,067.00+0.21%6,064.0+3.06019
2025-02-046,037.37+0.70%6,027.4+9.9755Housing, JOLTS
2025-02-035,994.62+0.77%5,993.9+0.8256ISM, Housing, Fed, Refunding
2025-01-276,012.80+0.47%5,994.4+18.47921Housing, Auctions
2025-01-135,835.15+0.95%5,809.9+25.29519
2025-01-105,826.27-0.78%5,838.5-12.34214NFP, UMich, EIA
2025-01-085,917.37+0.25%5,905.5+11.87913Claims, VIX settlement, EIA, Auctions
2024-12-305,907.25+0.14%5,918.0-10.7394
2024-12-275,971.39-0.48%5,962.8+8.6787UMich
2024-12-205,933.15+1.63%5,944.5-11.44214PCE, Opex
2024-12-195,867.92-0.91%5,900.4-32.43216GDP, Claims, EIA
2024-12-176,050.05+0.07%6,046.5+3.610013Retail sales, Auctions
2024-12-166,073.85+0.11%6,073.3+0.6268
2024-12-096,053.07-0.48%6,064.1-11.11110
2024-11-275,997.97-0.24%5,999.1-1.14525PCE, Housing, GDP, Claims, VIX settlement, EIA, Auctions
2024-11-185,893.12+0.37%5,891.7+1.45513
2024-11-155,870.39-0.73%5,871.4-1.0953Retail sales, Opex
2024-10-315,705.57-1.11%5,730.8-25.256PCE, Claims, EIA
2024-10-295,833.42+0.34%5,830.8+2.6208Confidence, JOLTS, Auctions
2024-10-285,824.36-0.21%5,832.1-7.8540Auctions, Refunding
2024-10-235,796.62-0.64%5,796.7-0.12517VIX settlement, EIA, Auctions
2024-10-225,851.67+0.41%5,843.5+8.2455
2024-10-165,842.72+0.47%5,828.8+13.9253VIX settlement
2024-10-095,793.82+0.81%5,773.6+20.2801VIX settlement, EIA, Auctions
2024-10-025,709.84+0.32%5,707.3+2.57519GDP, VIX settlement, EIA
2024-10-015,707.97-0.75%5,712.3-4.32018ISM, JOLTS, Housing
2024-09-045,520.47+0.15%5,523.2-2.73526Housing, VIX settlement, JOLTS
2024-08-295,592.71-0.29%5,620.4-27.7206GDP, Claims, EIA, Auctions
2024-08-275,626.30+0.40%5,620.8+5.5607Confidence
2024-08-065,238.87+0.62%5,272.0-33.1358Auctions
2024-08-055,187.74+1.20%5,201.7-14.06521ISM, Fed
2024-08-025,345.79-0.47%5,335.9+9.9805NFP, Housing
2024-07-245,427.81-1.46%5,461.5-33.6110Housing, VIX settlement, EIA, Auctions
2024-07-195,505.47-0.67%5,515.8-10.43212Opex
2024-07-175,589.10-0.40%5,596.6-7.53212Housing, VIX settlement, EIA, Auctions
2024-06-265,478.66+0.39%5,464.6+14.1753Housing, VIX settlement, EIA, Auctions, Fed
2024-06-215,467.02+0.06%5,464.7+2.33540Opex
2024-06-205,472.82-0.43%5,479.7-6.91514Housing, Claims, EIA
2024-06-175,472.55+0.91%5,450.7+21.9357
2024-06-145,431.25+0.33%5,419.7+11.5857UMich
2024-06-055,353.32+0.80%5,327.3+26.07011VIX settlement, ISM, EIA
2024-05-315,281.85+0.70%5,218.4+63.5659PCE, Opex
2024-05-285,306.14-0.09%5,301.6+4.65523Confidence, Auctions
2024-05-245,304.00+0.34%5,301.1+2.98015Housing, UMich
2024-05-235,267.81-1.26%5,300.9-33.01516Housing, Claims, EIA
2024-05-015,020.27-0.22%5,055.1-34.8608Refunding, VIX settlement, ISM, JOLTS, Housing, EIA, FOMC
2024-04-265,100.26+0.46%5,103.1-2.8406PCE, UMich
2024-04-255,048.87+0.82%5,029.2+19.69011GDP, Claims, EIA, Auctions
2024-04-235,070.45+0.81%5,064.9+5.6552Housing, Retail sales
2024-04-225,009.87+0.34%5,010.4-0.51016
2024-04-194,965.00-0.82%4,981.6-16.6010Opex
2024-04-175,022.95-0.98%5,036.8-13.9308VIX settlement, EIA, Auctions
2024-04-155,061.25-1.99%5,097.1-35.856Retail sales
2024-04-105,161.75+0.23%5,157.4+4.46519CPI, VIX settlement, EIA, Auctions
2024-04-095,209.79-0.22%5,189.3+20.51009Auctions
2024-04-055,204.69+0.84%5,199.4+5.34524NFP
2024-04-035,212.30+0.31%5,217.9-5.6258VIX settlement, ISM, EIA
2024-04-025,206.17+0.06%5,196.8+9.49513Housing, JOLTS
2024-04-015,243.57-0.22%5,241.4+2.2356ISM, Housing
2024-03-285,255.32+0.10%5,252.6+2.8408GDP, Claims, EIA
2024-03-265,204.49-0.48%5,226.8-22.41022Housing, Confidence, Auctions
2024-03-255,219.07-0.00%5,225.9-6.84046Housing
2024-03-195,177.35+0.75%5,161.9+15.4807Housing, Auctions
2024-03-135,165.45-0.20%5,169.4-4.01524VIX settlement, EIA, Auctions
2024-03-055,078.42-0.61%5,082.2-3.8302Housing, ISM
2024-02-295,095.17+0.10%5,084.4+10.85511PCE, Claims, EIA, Opex
2024-02-214,981.46+0.33%4,961.1+20.35531VIX settlement, Auctions

Showing the first 200 of 387; the JSON carries all of them.

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.