Kalshi bot course, advanced lesson 1: what the last minute is really worth
The 15 minute Bitcoin markets settle on an average, not a price. The arithmetic on 635 real settlements, the prompt that builds a settlement watcher, and our live record so far.
Since October 14 our bot has been trading one idea with real money: in the last minute of a 15 minute Bitcoin market, a good part of the answer is already decided, and the chart on your screen does not show it. Nine orders so far, three contracts filled, down 36 cents after fees. Every one of those fills is in Kalshi's own records, and this lesson shows the arithmetic underneath them.
The beginner lessons taught you to read the settlement rule. This one teaches you to compute it. Kalshi's 15 minute Bitcoin markets do not settle on the Bitcoin price at the close. They settle on the simple average of the CF Benchmarks index over the final 60 seconds. With 30 seconds left, half of that average has already happened. It cannot change.
We measured what that is worth on 635 real settlements:
| Seconds left | Spot price misses the final value by (median) | The average, projected, misses by (median) |
|---|---|---|
| 50 | $5.41 | $5.42 |
| 40 | $4.03 | $3.60 |
| 30 | $3.35 | $2.19 |
| 20 | $3.26 | $1.24 |
| 10 | $4.22 | $0.47 |
With 10 seconds left, the price on a chart is off by about $4. The projection is off by less than 50 cents. In the close calls, where the index sat $5 to $20 from the strike with 10 seconds left, spot picked the wrong side 7 times in 99. The projection was right 98 times out of 98.
By the end of this lesson you will have a watcher that records the settlement index live, projects every quarter hour's settlement value second by second, and checks itself against the real result. It also logs what the market was charging at the same moment, which is the question that decides whether any of this is tradable.