# Weekly Prediction Market Volume

Compare weekly prediction market contract volume, venue shares, and trends for Kalshi, Polymarket, and Polymarket US, with live charts and data-backed analysis.

Author: Outcome researcher

Source: https://app.outcome.sh/share/notebooks/7e9df8c3-3fce-476f-84ec-87193cc4892e

Created: 2026-10-27T21:06:52.803Z

Updated: 2026-10-27T22:08:46.835Z

This notebook compares weekly prediction market trading volume across Kalshi, Polymarket, and Polymarket US. It examines the scale of recorded contract activity, each venue’s share of the tracked total, and changes across completed weeks. The analysis combines historical charts with query-backed comparisons that update when the notebook refreshes.

## Weekly prediction market volume over time

## Figure 1. Weekly prediction market contract volume by venue

Weekly contract quantity for records with count \> 1. Sunday-start weeks; the current week is incomplete.

Cached source data for the selected chart columns, before chart aggregation, bucketing, normalization, top-N, zoom, and plot ordering. Values retain their source precision.

| trade\_date | venue         | daily\_volume      |
| ----------- | ------------- | ------------------ |
| 2026-10-25  | kalshi        | 10095848591.23021  |
| 2026-10-25  | polymarket    | 755668565.6598269  |
| 2026-10-25  | polymarket-us | 1391334787.5380409 |
| 2026-10-18  | kalshi        | 24528362574.290524 |
| 2026-10-18  | polymarket    | 2127478375.6387208 |
| 2026-10-18  | polymarket-us | 5258651154.731394  |
| 2026-10-11  | kalshi        | 21243376555.00728  |
| 2026-10-11  | polymarket    | 1872787829.0173035 |
| 2026-10-11  | polymarket-us | 3276987160.8166924 |
| 2026-10-04  | kalshi        | 18704611929.657284 |
| 2026-10-04  | polymarket    | 1648314234.8395898 |
| 2026-10-04  | polymarket-us | 2766264515.3581195 |
| 2026-09-27  | kalshi        | 17706623832.066628 |
| 2026-09-27  | polymarket    | 986985578.6845012  |
| 2026-09-27  | polymarket-us | 2807109712.22644   |
| 2026-09-20  | kalshi        | 15581101477.650112 |
| 2026-09-20  | polymarket    | 993097203.5960764  |
| 2026-09-20  | polymarket-us | 2686647746.769564  |
| 2026-09-13  | kalshi        | 14654782046.024837 |
| 2026-09-13  | polymarket    | 1034360675.0508149 |
| 2026-09-13  | polymarket-us | 2166135153.7912173 |
| 2026-09-06  | kalshi        | 12180713442.393229 |
| 2026-09-06  | polymarket    | 1045394971.7917688 |
| 2026-09-06  | polymarket-us | 1474532770.5499349 |
| 2026-08-30  | kalshi        | 11793507360.938843 |
| 2026-08-30  | polymarket    | 986435626.4242572  |
| 2026-08-30  | polymarket-us | 966000244.4402972  |
| 2026-08-23  | kalshi        | 9890037072.32712   |
| 2026-08-23  | polymarket    | 1072948177.7479811 |
| 2026-08-23  | polymarket-us | 886633991.3102369  |
| 2026-08-16  | kalshi        | 8976380706.316315  |
| 2026-08-16  | polymarket    | 1116855560.553892  |
| 2026-08-16  | polymarket-us | 879588275.4001409  |
| 2026-08-09  | kalshi        | 8446047873.349983  |
| 2026-08-09  | polymarket    | 976353631.2012383  |
| 2026-08-09  | polymarket-us | 803973728.7800171  |
| 2026-08-02  | kalshi        | 8128047512.116436  |
| 2026-08-02  | polymarket    | 941560560.0262803  |
| 2026-08-02  | polymarket-us | 854031253.9001039  |
| 2026-07-26  | kalshi        | 8312101407.062036  |
| 2026-07-26  | polymarket    | 1031246358.9970526 |
| 2026-07-26  | polymarket-us | 860532693.6899703  |
| 2026-07-19  | kalshi        | 8832279538.08934   |
| 2026-07-19  | polymarket    | 1244387750.0031333 |
| 2026-07-19  | polymarket-us | 947241390.6803229  |
| 2026-07-12  | kalshi        | 8491320312.6578455 |
| 2026-07-12  | polymarket    | 1635759698.9799895 |
| 2026-07-12  | polymarket-us | 1219847494.7798793 |
| 2026-07-05  | kalshi        | 10307658554.3448   |
| 2026-07-05  | polymarket    | 2412513074.230613  |
| 2026-07-05  | polymarket-us | 1136587103.9997928 |
| 2026-06-28  | kalshi        | 10429069098.843107 |
| 2026-06-28  | polymarket    | 2923438831.4953175 |
| 2026-06-28  | polymarket-us | 1275241491.1111727 |
| 2026-06-21  | kalshi        | 10696060021.631618 |
| 2026-06-21  | polymarket    | 2731510238.0208087 |
| 2026-06-21  | polymarket-us | 1351545075.9006114 |
| 2026-06-14  | kalshi        | 8820543729.449045  |
| 2026-06-14  | polymarket    | 3009373802.3999476 |
| 2026-06-14  | polymarket-us | 1140867722.4721115 |
| 2026-06-07  | kalshi        | 5475882328.958631  |
| 2026-06-07  | polymarket    | 2107467829.4824853 |
| 2026-06-07  | polymarket-us | 621623099.3402138  |
| 2026-05-31  | kalshi        | 4493187384.655816  |
| 2026-05-31  | polymarket    | 1939606599.3759413 |
| 2026-05-31  | polymarket-us | 482830745.80000496 |
| 2026-05-24  | kalshi        | 4231842863.894392  |
| 2026-05-24  | polymarket    | 1654201164.3088818 |
| 2026-05-24  | polymarket-us | 447275697          |
| 2026-05-17  | kalshi        | 3954121686.6102257 |
| 2026-05-17  | polymarket    | 1640841898.5882823 |
| 2026-05-17  | polymarket-us | 436871515          |
| 2026-05-10  | kalshi        | 3984764170.2335835 |
| 2026-05-10  | polymarket    | 1558915637.9518259 |
| 2026-05-10  | polymarket-us | 403779257          |
| 2026-05-03  | kalshi        | 3949795684.2135086 |
| 2026-05-03  | polymarket    | 1560970844.6855261 |
| 2026-05-03  | polymarket-us | 321545108          |
| 2026-04-26  | kalshi        | 3917140984.2336464 |
| 2026-04-26  | polymarket    | 1800557541.798543  |
| 2026-04-26  | polymarket-us | 309462771          |
| 2026-04-19  | kalshi        | 3721693406.711596  |
| 2026-04-19  | polymarket    | 1977029176.5788867 |
| 2026-04-19  | polymarket-us | 235897047          |
| 2026-04-12  | kalshi        | 3063293055.013469  |
| 2026-04-12  | polymarket    | 2092135404.8129127 |
| 2026-04-12  | polymarket-us | 227889663          |
| 2026-04-05  | kalshi        | 3466892269.040561  |
| 2026-04-05  | polymarket    | 2422259950.866857  |
| 2026-04-05  | polymarket-us | 459030948          |
| 2026-03-29  | kalshi        | 2857733953.869858  |
| 2026-03-29  | polymarket    | 1989224324.3171463 |
| 2026-03-29  | polymarket-us | 214371015          |
| 2026-03-22  | kalshi        | 2861275076.2099876 |
| 2026-03-22  | polymarket    | 2289698907.0929174 |
| 2026-03-22  | polymarket-us | 268861451          |
| 2026-03-15  | kalshi        | 3259432219.11      |
| 2026-03-15  | polymarket    | 2509117087.3368363 |
| 2026-03-15  | polymarket-us | 177565973          |
| 2026-03-08  | kalshi        | 2972593907.17      |
| 2026-03-08  | polymarket    | 2367382557.0507064 |
| 2026-03-08  | polymarket-us | 82624166           |
| 2026-03-01  | kalshi        | 2790199994         |
| 2026-03-01  | polymarket    | 2511814922.4807825 |
| 2026-03-01  | polymarket-us | 81049073           |
| 2026-02-22  | kalshi        | 2747692467         |
| 2026-02-22  | polymarket    | 2304620863.7967124 |
| 2026-02-22  | polymarket-us | 80727186           |
| 2026-02-15  | kalshi        | 2445060246         |
| 2026-02-15  | polymarket    | 1817233523.9666345 |
| 2026-02-15  | polymarket-us | 60286267           |
| 2026-02-08  | kalshi        | 3006394223         |
| 2026-02-08  | polymarket    | 1910930321.7562284 |
| 2026-02-08  | polymarket-us | 66485266           |
| 2026-02-01  | kalshi        | 2212686085         |
| 2026-02-01  | polymarket    | 1907430106.5551121 |
| 2026-02-01  | polymarket-us | 57289939           |
| 2026-01-25  | kalshi        | 2420664570         |
| 2026-01-25  | polymarket    | 2059121194.708716  |
| 2026-01-25  | polymarket-us | 73869127           |
| 2026-01-18  | kalshi        | 2222657184         |
| 2026-01-18  | polymarket    | 1750423980.4515235 |
| 2026-01-18  | polymarket-us | 66088936           |
| 2026-01-11  | kalshi        | 2165330986         |
| 2026-01-11  | polymarket    | 1817564174.431439  |
| 2026-01-11  | polymarket-us | 73432743           |
| 2026-01-04  | kalshi        | 1851669139         |
| 2026-01-04  | polymarket    | 1899898960.3026147 |
| 2026-01-04  | polymarket-us | 52887510           |
| 2025-12-28  | kalshi        | 1940090752         |
| 2025-12-28  | polymarket    | 2111907972.720938  |
| 2025-12-28  | polymarket-us | 43687034           |
| 2025-12-21  | kalshi        | 1738974252         |
| 2025-12-21  | polymarket    | 1964702956.6218388 |
| 2025-12-21  | polymarket-us | 29880534           |
| 2025-12-14  | kalshi        | 1507799326         |
| 2025-12-14  | polymarket    | 2063093333.4161096 |
| 2025-12-14  | polymarket-us | 17655605           |
| 2025-12-07  | kalshi        | 1265966814         |
| 2025-12-07  | polymarket    | 1916851840.4589648 |
| 2025-12-07  | polymarket-us | 7101410            |
| 2025-11-30  | kalshi        | 1269022897         |
| 2025-11-30  | polymarket    | 1860900628.2706966 |
| 2025-11-30  | polymarket-us | 5406403            |
| 2025-11-23  | kalshi        | 1483317637         |
| 2025-11-23  | polymarket    | 1882684573.0378244 |
| 2025-11-23  | polymarket-us | 766578             |
| 2025-11-16  | kalshi        | 1145754821         |
| 2025-11-16  | polymarket    | 1726828880.6190178 |
| 2025-11-16  | polymarket-us | 782028             |
| 2025-11-09  | kalshi        | 1217918643         |
| 2025-11-09  | polymarket    | 1908059424.4563184 |
| 2025-11-09  | polymarket-us | 46387              |
| 2025-11-02  | kalshi        | 1286885495         |
| 2025-11-02  | polymarket    | 1819047561.6912634 |
| 2025-11-02  | polymarket-us | 13474              |
| 2025-10-26  | kalshi        | 1173852116         |
| 2025-10-26  | polymarket    | 2634254246.6722193 |
| 2025-10-26  | polymarket-us | 1969               |
| 2025-10-19  | kalshi        | 1095060305         |
| 2025-10-19  | polymarket    | 2709447892.1997447 |
| 2025-10-19  | polymarket-us | 0                  |
| 2025-10-12  | kalshi        | 907437002          |
| 2025-10-12  | polymarket    | 2287081102.4906044 |
| 2025-10-12  | polymarket-us | 0                  |
| 2025-10-05  | kalshi        | 987604025          |
| 2025-10-05  | polymarket    | 1574762430.1342144 |
| 2025-10-05  | polymarket-us | 0                  |
| 2025-09-28  | kalshi        | 938534678          |
| 2025-09-28  | polymarket    | 904629223.1388837  |
| 2025-09-28  | polymarket-us | 0                  |
| 2025-09-21  | kalshi        | 775676878          |
| 2025-09-21  | polymarket    | 647111187.4297197  |
| 2025-09-21  | polymarket-us | 0                  |
| 2025-09-14  | kalshi        | 697099146          |
| 2025-09-14  | polymarket    | 448508715.53882945 |
| 2025-09-14  | polymarket-us | 0                  |
| 2025-09-07  | kalshi        | 556550198          |
| 2025-09-07  | polymarket    | 327127304.82997787 |
| 2025-09-07  | polymarket-us | 0                  |
| 2025-08-31  | kalshi        | 415784785          |
| 2025-08-31  | polymarket    | 309709550.7474681  |
| 2025-08-31  | polymarket-us | 0                  |
| 2025-08-24  | kalshi        | 257326187          |
| 2025-08-24  | polymarket    | 259871064.56590986 |
| 2025-08-24  | polymarket-us | 0                  |
| 2025-08-17  | kalshi        | 190531506          |
| 2025-08-17  | polymarket    | 270446930.7730106  |
| 2025-08-17  | polymarket-us | 0                  |
| 2025-08-10  | kalshi        | 170569056          |
| 2025-08-10  | polymarket    | 248981040.19906795 |
| 2025-08-10  | polymarket-us | 0                  |
| 2025-08-03  | kalshi        | 131559935          |
| 2025-08-03  | polymarket    | 215295350.08168244 |
| 2025-08-03  | polymarket-us | 0                  |
| 2025-07-27  | kalshi        | 156882892          |
| 2025-07-27  | polymarket    | 281064463.4258917  |
| 2025-07-27  | polymarket-us | 0                  |
| 2025-07-20  | kalshi        | 161427949          |
| 2025-07-20  | polymarket    | 243597682.68042928 |

Showing the first 200 of 954 rows.

Cached: 2026-10-27T21:13:57.468Z.

## Figure 2. Weekly contract-volume share by venue

Share of qualifying weekly contract quantity across the three tracked venues (%).

Cached source data for the selected chart columns, before chart aggregation, bucketing, normalization, top-N, zoom, and plot ordering. Values retain their source precision.

| trade\_date | venue         | market\_share\_pct     |
| ----------- | ------------- | ---------------------- |
| 2026-10-25  | kalshi        | 82.46320903868316      |
| 2026-10-25  | polymarket    | 6.172324627381809      |
| 2026-10-25  | polymarket-us | 11.364466333935045     |
| 2026-10-18  | kalshi        | 76.8565029763031       |
| 2026-10-18  | polymarket    | 6.666182775717851      |
| 2026-10-18  | polymarket-us | 16.477314247979045     |
| 2026-10-11  | kalshi        | 80.4882149784778       |
| 2026-10-11  | polymarket    | 7.095734004465082      |
| 2026-10-11  | polymarket-us | 12.416051017057121     |
| 2026-10-04  | kalshi        | 80.90513283389123      |
| 2026-10-04  | polymarket    | 7.129636403214822      |
| 2026-10-04  | polymarket-us | 11.965230762893945     |
| 2026-09-27  | kalshi        | 82.35363538675209      |
| 2026-09-27  | polymarket    | 4.590477058182306      |
| 2026-09-27  | polymarket-us | 13.055887555065608     |
| 2026-09-20  | kalshi        | 80.89520642761946      |
| 2026-09-20  | polymarket    | 5.156041336540499      |
| 2026-09-20  | polymarket-us | 13.948752235840042     |
| 2026-09-13  | kalshi        | 82.07535132596811      |
| 2026-09-13  | polymarket    | 5.793024798044634      |
| 2026-09-13  | polymarket-us | 12.131623875987245     |
| 2026-09-06  | kalshi        | 82.85838208908612      |
| 2026-09-06  | polymarket    | 7.1112202430823315     |
| 2026-09-06  | polymarket-us | 10.030397667831537     |
| 2026-08-30  | kalshi        | 85.79627575976534      |
| 2026-08-30  | polymarket    | 7.176194530921555      |
| 2026-08-30  | polymarket-us | 7.027529709313101      |
| 2026-08-23  | kalshi        | 83.46291024934973      |
| 2026-08-23  | polymarket    | 9.054705943636234      |
| 2026-08-23  | polymarket-us | 7.4823838070140445     |
| 2026-08-16  | kalshi        | 81.80556129132312      |
| 2026-08-16  | polymarket    | 10.17837801243842      |
| 2026-08-16  | polymarket-us | 8.016060696238458      |
| 2026-08-09  | kalshi        | 82.59082696106668      |
| 2026-08-09  | polymarket    | 9.547406670732844      |
| 2026-08-09  | polymarket-us | 7.861766368200463      |
| 2026-08-02  | kalshi        | 81.90591420211963      |
| 2026-08-02  | polymarket    | 9.488057043299857      |
| 2026-08-02  | polymarket-us | 8.606028754580503      |
| 2026-07-26  | kalshi        | 81.46019977253295      |
| 2026-07-26  | polymarket    | 10.106413565554588     |
| 2026-07-26  | polymarket-us | 8.433386661912474      |
| 2026-07-19  | kalshi        | 80.11930972447577      |
| 2026-07-19  | polymarket    | 11.288081081434184     |
| 2026-07-19  | polymarket-us | 8.592609194090056      |
| 2026-07-12  | kalshi        | 74.8336526152585       |
| 2026-07-12  | polymarket    | 14.415882167704162     |
| 2026-07-12  | polymarket-us | 10.750465217037346     |
| 2026-07-05  | kalshi        | 74.38722686361716      |
| 2026-07-05  | polymarket    | 17.410370785767878     |
| 2026-07-05  | polymarket-us | 8.202402350614962      |
| 2026-06-28  | kalshi        | 71.29647082653946      |
| 2026-06-28  | polymarket    | 19.98556816408472      |
| 2026-06-28  | polymarket-us | 8.717961009375818      |
| 2026-06-21  | kalshi        | 72.37280296406435      |
| 2026-06-21  | polymarket    | 18.48223101317718      |
| 2026-06-21  | polymarket-us | 9.144966022758467      |
| 2026-06-14  | kalshi        | 68.00315907250533      |
| 2026-06-14  | polymarket    | 23.20116896081832      |
| 2026-06-14  | polymarket-us | 8.795671966676354      |
| 2026-06-07  | kalshi        | 66.73857618933104      |
| 2026-06-07  | polymarket    | 25.685249217403985     |
| 2026-06-07  | polymarket-us | 7.576174593264964      |
| 2026-05-31  | kalshi        | 64.9715327275302       |
| 2026-05-31  | polymarket    | 28.046730051865122     |
| 2026-05-31  | polymarket-us | 6.981737220604665      |
| 2026-05-24  | kalshi        | 66.81871510534812      |
| 2026-05-24  | polymarket    | 26.119021872937083     |
| 2026-05-24  | polymarket-us | 7.062263021714797      |
| 2026-05-17  | kalshi        | 65.55420731710811      |
| 2026-05-17  | polymarket    | 27.203029780013086     |
| 2026-05-17  | polymarket-us | 7.242762902878803      |
| 2026-05-10  | kalshi        | 66.99943835778818      |
| 2026-05-10  | polymarket    | 26.211456369279396     |
| 2026-05-10  | polymarket-us | 6.789105272932423      |
| 2026-05-03  | kalshi        | 67.72264464101174      |
| 2026-05-03  | polymarket    | 26.764187887523004     |
| 2026-05-03  | polymarket-us | 5.513167471465249      |
| 2026-04-26  | kalshi        | 64.99147428097652      |
| 2026-04-26  | polymarket    | 29.874056011826802     |
| 2026-04-26  | polymarket-us | 5.134469707196676      |
| 2026-04-19  | kalshi        | 62.71157443209936      |
| 2026-04-19  | polymarket    | 33.31349437271545      |
| 2026-04-19  | polymarket-us | 3.974931195185184      |
| 2026-04-12  | kalshi        | 56.903437343308276     |
| 2026-04-12  | polymarket    | 38.863306181773396     |
| 2026-04-12  | polymarket-us | 4.233256474918336      |
| 2026-04-05  | kalshi        | 54.61235407584134      |
| 2026-04-05  | polymarket    | 38.1567432255632       |
| 2026-04-05  | polymarket-us | 7.230902698595456      |
| 2026-03-29  | kalshi        | 56.46212266245193      |
| 2026-03-29  | polymarket    | 39.30240869715428      |
| 2026-03-29  | polymarket-us | 4.235468640393786      |
| 2026-03-22  | kalshi        | 52.79265599284755      |
| 2026-03-22  | polymarket    | 42.246650010830386     |
| 2026-03-22  | polymarket-us | 4.960693996322062      |
| 2026-03-15  | kalshi        | 54.81616258562049      |
| 2026-03-15  | polymarket    | 42.19758564065811      |
| 2026-03-15  | polymarket-us | 2.9862517737213943     |
| 2026-03-08  | kalshi        | 54.81860291542458      |
| 2026-03-08  | polymarket    | 43.65769708093644      |
| 2026-03-08  | polymarket-us | 1.5237000036389752     |
| 2026-03-01  | kalshi        | 51.83293379852848      |
| 2026-03-01  | polymarket    | 46.661435334768456     |
| 2026-03-01  | polymarket-us | 1.5056308667030633     |
| 2026-02-22  | kalshi        | 53.529530071091365     |
| 2026-02-22  | polymarket    | 44.897772699345786     |
| 2026-02-22  | polymarket-us | 1.5726972295628403     |
| 2026-02-15  | kalshi        | 56.5648345453383       |
| 2026-02-15  | polymarket    | 42.04048296215878      |
| 2026-02-15  | polymarket-us | 1.3946824925029222     |
| 2026-02-08  | kalshi        | 60.323213307849294     |
| 2026-02-08  | polymarket    | 38.34276174889325      |
| 2026-02-08  | polymarket-us | 1.33402494325745       |
| 2026-02-01  | kalshi        | 52.96794268614646      |
| 2026-02-01  | polymarket    | 45.660633583205005     |
| 2026-02-01  | polymarket-us | 1.3714237306485464     |
| 2026-01-25  | kalshi        | 53.15871816301979      |
| 2026-01-25  | polymarket    | 45.21908760494694      |
| 2026-01-25  | polymarket-us | 1.622194232033278      |
| 2026-01-18  | kalshi        | 55.027570731708906     |
| 2026-01-18  | polymarket    | 43.33622840632164      |
| 2026-01-18  | polymarket-us | 1.6362008619694468     |
| 2026-01-11  | kalshi        | 53.381556855111356     |
| 2026-01-11  | polymarket    | 44.808117531471645     |
| 2026-01-11  | polymarket-us | 1.8103256134169967     |
| 2026-01-04  | kalshi        | 48.67106701080486      |
| 2026-01-04  | polymarket    | 49.93878639711295      |
| 2026-01-04  | polymarket-us | 1.3901465920821896     |
| 2025-12-28  | kalshi        | 47.36913099031017      |
| 2025-12-28  | polymarket    | 51.5642091980337       |
| 2025-12-28  | polymarket-us | 1.0666598116561374     |
| 2025-12-21  | kalshi        | 46.576867745959376     |
| 2025-12-21  | polymarket    | 52.62280891475255      |
| 2025-12-21  | polymarket-us | 0.8003233392880865     |
| 2025-12-14  | kalshi        | 42.01697218207355      |
| 2025-12-14  | polymarket    | 57.49102927982478      |
| 2025-12-14  | polymarket-us | 0.49199853810166694    |
| 2025-12-07  | kalshi        | 39.68647453285691      |
| 2025-12-07  | polymarket    | 60.090905155144625     |
| 2025-12-07  | polymarket-us | 0.22262031199845925    |
| 2025-11-30  | kalshi        | 40.474939672455285     |
| 2025-11-30  | polymarket    | 59.3526254283894       |
| 2025-11-30  | polymarket-us | 0.17243489915531546    |
| 2025-11-23  | kalshi        | 44.0576033100416       |
| 2025-11-23  | polymarket    | 55.919627737046525     |
| 2025-11-23  | polymarket-us | 0.022768952911873905   |
| 2025-11-16  | kalshi        | 39.875008224306924     |
| 2025-11-16  | polymarket    | 60.09777533081318      |
| 2025-11-16  | polymarket-us | 0.027216444879910567   |
| 2025-11-09  | kalshi        | 38.960624292743155     |
| 2025-11-09  | polymarket    | 61.03789180971619      |
| 2025-11-09  | polymarket-us | 0.0014838975406565615  |
| 2025-11-02  | kalshi        | 41.43295714474483      |
| 2025-11-02  | polymarket    | 58.56660904224948      |
| 2025-11-02  | polymarket-us | 0.00043381300569270294 |
| 2025-10-26  | kalshi        | 30.825071499069914     |
| 2025-10-26  | polymarket    | 69.17487679546825      |
| 2025-10-26  | polymarket-us | 0.00005170546183320818 |
| 2025-10-19  | kalshi        | 28.783228954691275     |
| 2025-10-19  | polymarket    | 71.21677104530872      |
| 2025-10-19  | polymarket-us | 0                      |
| 2025-10-12  | kalshi        | 28.40606853110007      |
| 2025-10-12  | polymarket    | 71.59393146889992      |
| 2025-10-12  | polymarket-us | 0                      |
| 2025-10-05  | kalshi        | 38.54265353111916      |
| 2025-10-05  | polymarket    | 61.45734646888085      |
| 2025-10-05  | polymarket-us | 0                      |
| 2025-09-28  | kalshi        | 50.919762340184896     |
| 2025-09-28  | polymarket    | 49.08023765981511      |
| 2025-09-28  | polymarket-us | 0                      |
| 2025-09-21  | kalshi        | 54.5180899985779       |
| 2025-09-21  | polymarket    | 45.4819100014221       |
| 2025-09-21  | polymarket-us | 0                      |
| 2025-09-14  | kalshi        | 60.84971737743024      |
| 2025-09-14  | polymarket    | 39.15028262256977      |
| 2025-09-14  | polymarket-us | 0                      |
| 2025-09-07  | kalshi        | 62.98114371109908      |
| 2025-09-07  | polymarket    | 37.01885628890092      |
| 2025-09-07  | polymarket-us | 0                      |
| 2025-08-31  | kalshi        | 57.310548754542914     |
| 2025-08-31  | polymarket    | 42.68945124545708      |
| 2025-08-31  | polymarket-us | 0                      |
| 2025-08-24  | kalshi        | 49.7539741792706       |
| 2025-08-24  | polymarket    | 50.24602582072941      |
| 2025-08-24  | polymarket-us | 0                      |
| 2025-08-17  | kalshi        | 41.3319779844321       |
| 2025-08-17  | polymarket    | 58.66802201556789      |
| 2025-08-17  | polymarket-us | 0                      |
| 2025-08-10  | kalshi        | 40.65522986295979      |
| 2025-08-10  | polymarket    | 59.344770137040214     |
| 2025-08-10  | polymarket-us | 0                      |
| 2025-08-03  | kalshi        | 37.92934421311135      |
| 2025-08-03  | polymarket    | 62.07065578688864      |
| 2025-08-03  | polymarket-us | 0                      |
| 2025-07-27  | kalshi        | 35.82231746722976      |
| 2025-07-27  | polymarket    | 64.17768253277023      |
| 2025-07-27  | polymarket-us | 0                      |
| 2025-07-20  | kalshi        | 39.85623041441704      |
| 2025-07-20  | polymarket    | 60.14376958558296      |

Showing the first 200 of 954 rows.

Cached: 2026-10-27T21:13:57.468Z.

Figures 1 and 2. Weekly contract volume and venue shares for Kalshi, Polymarket, and Polymarket US. Each bar aggregates qualifying records within a Sunday-start week. The share chart expresses each venue’s contribution as a percentage of the combined tracked volume. The newest week is incomplete; historical observations can also be revised when source records change.

## Kalshi vs Polymarket:

For the completed week beginning 2026-10-18, qualifying contract volume totals 31,914,492,105. Kalshi contributes 24,528,362,574 contracts (76.86%), compared with 2,127,478,376 (6.67%) for Polymarket and 5,258,651,155 (16.48%) for Polymarket US. 

| Venue         | Weekly contracts | Share (%) | Week-on-week (%) | Four-week average | Four-week change (%) |
| ------------- | ---------------- | --------- | ---------------- | ----------------- | -------------------- |
| Kalshi        | 24,528,362,574   | 76.86     | 15.46            | 20,545,743,723    | 51.60                |
| Polymarket    | 2,127,478,376    | 6.67      | 13.60            | 1,658,891,505     | 63.47                |
| Polymarket US | 5,258,651,155    | 16.48     | 60.47            | 3,527,253,136     | 93.45                |

Kalshi’s weekly market share changed by -3.63%, compared with -0.43% for Polymarket and 4.06% for Polymarket US. 

## Frequently asked questions about prediction market volume

### How is weekly prediction market volume measured here?

Weekly volume sums the count field for qualifying trade records, grouped by venue and Sunday-start week. It is a measure of recorded contract quantity. The count-greater-than-one filter excludes single-contract records, so the result should not be described as the volume of every trade on each platform.

### How do Kalshi and Polymarket compare?

Table 1 compares Kalshi and Polymarket over the same completed week, with Polymarket US shown separately. The volume difference and ratio describe relative scale, while weekly growth and share changes describe recent movement. The four-week comparison provides a longer window and can differ from the pattern in any single week.

### Does higher trading volume imply greater liquidity?

Volume alone does not establish order-book depth, narrower spreads, or lower execution costs. Those properties require separate evidence. Nor is summed contract quantity equivalent to cash paid: the source query does not multiply quantity by transaction price or normalize settlement payouts across products.

### Why can a venue’s volume rise while its share falls?

Venue share depends on both its own volume and the combined volume of the comparison group. If other venues grow faster, a venue can record more contracts and a smaller share at the same time. Percentage-point changes in share should therefore be interpreted alongside percentage changes in volume.

### Why can the most recent week appear lower than earlier weeks?

The current week contains only the activity recorded so far. A lower provisional bar does not establish a decline relative to a completed week. The numerical comparisons in this notebook use the latest completed week; the current week and the rolling average that includes it remain provisional.

### Will the charts and numerical analysis update together?

The weekly figures, comparison table, dates, and numerical statements reference the same saved query results. Refreshing the notebook recomputes them together. Mathematical definitions and explanatory prose remain fixed, while the empirical quantities update. Missing or undefined ratios display as a dash.

Data comes from cached results. This export does not run or refresh queries.

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