Companies added to SP500 is a one-time financials series on Kalshi, with markets like “Will Curtiss-Wright Corporation be added to the S&P 500 in Q3 2026?”. The Kalshi Eye archive lists 57 of its markets and has 12 days of daily Parquet files from October 12, 2026 to October 23, 2026 (684 KB), with every order book change and trade.

Venue: Kalshi, series KXSP500ADDQ
Category: Financials, one-time
Markets: 57 (22 settled, 35 open)
Files: 12 days, October 12, 2026 to October 23, 2026, 684 KB, 168,729 rows
Datasets: Order book (L2, incremental), Order book snapshots (top 10, 1 second), Top of book (every change), Top of book (1-minute bars), Trades

Open Companies added to SP500 in Markets to see every day and market, then export the days you need. Free sample files of each dataset are on the Kalshi data page.

Reading the files

Every KXSP500ADDQ trade on October 23, 2026, in DuckDB:

SELECT ts_recv, ticker, yes_price, size, taker_side
FROM 'kalshieye-data/trades/date=2026-10-23/series=KXSP500ADDQ/trades-KXSP500ADDQ-2026-10-23.parquet'
ORDER BY ts_recv;

To test a strategy on this series, see How to backtest Kalshi markets.

Related Kalshi series

Nasdaq above/below (KXNASDAQ100U): 25,440 markets, 12 days of files
S&P 500 above/below (KXINXU): 4,180 markets, 12 days of files
DJI Hourly (KXDJI): 2,210 markets, 12 days of files
NKY Hourly (KXNKY): 2,180 markets, 3 days of files
US 7Y Treasury yield hourly (KX7YRRATEH): 1,963 markets, 7 days of files
US 5Y Treasury yield hourly (KX5YRRATEH): 1,850 markets, 7 days of files

Figures as of October 24, 2026. All Kalshi series with pages are listed on Kalshi series.