US Index Markets 2026 — S&P and Nasdaq

Four Kalshi index books carry $7,914,325 of open interest between them. They traded $29,419 yesterday. That is a 269-to-1 ratio, and it means these books are not really price discovery—they are a warehouse.

What is warehoused is the crash.

• S&P year-end ($4,096,122 of open interest, $15,591 a day): the single deepest position is $407,087 on 3,999.99 or below at 1.5%—a bucket 47% below where the index trades.
• Nasdaq-100 year-end ($2,929,499, $7,008 a day): $1,098,646—37% of the entire book—sits on 18,999.99 or below at 4.5%.
• Year-low ladder ($381,765): deepest position $144,316 on 5,900 or below at 8.2%.
• Year-high ladder ($506,939): implies a 2026 high near 8,101, and its deepest position is $157,186 on 7,800 or above at exactly 50%.

$1.5M of that $7.9M sits on two contracts, both deep-crash buckets, both priced under 5%. Whatever those positions are—portfolio insurance is the obvious guess—they dwarf everything else on the page.

Meanwhile the daily tape has moved to the other exchange. Polymarket's S&P daily up/down turned $74,613 on Friday against Kalshi's $608—a 123-to-1 gap on the same question, the same day.

Today's tape: Monday's S&P and Nasdaq-100 close ladders, and the daily up/down contract.

These are thin—$181 and $101—which is the point. Kalshi's index dailies barely trade. The daily volume in US index event contracts is on Polymarket, and it is roughly a hundred times larger.

The year ladders. The high ladder implies a 2026 peak around 8,101 and has $157,186 parked on 7,800 or above at exactly 50%—a coin flip the book cannot break, holding the largest single position in it.

The low ladder is where the shape gets interesting: it never crosses 50% at any strike, and its deepest position is $144,316 on 5,900 or below at 8.2%. The most-traded rung is 6,300 or below at 18.25%, on $734.

Neither of these books is trading. Both are holding.

The two contracts that hold $1.5M between them, spotlighted because they are the whole story of this page.

S&P below 4,000 at 1.5% ($407,087) and Nasdaq-100 below 19,000 at 4.5% ($1,098,646). Between them they carry 19% of all open interest in Kalshi's index complex, and their combined 24-hour volume is a rounding error.

The honest reading is that these are hedges, not forecasts. A book that prices a 47% drawdown at 1.5% and simultaneously holds four hundred thousand dollars there is describing insurance demand, not consensus. It is also the single best argument for why event contracts and options belong in the same account—this is a put by another name, and nothing on the page tells you that.

Cross-exchange, and the context books.

Manifold's S&P year-end ladder is the only non-Kalshi ladder with a comparable structure. Polymarket's spx-hit-dec-2026 book has already closed five rungs—the index has printed 7,400, 7,600 and 7,800 this year and has not printed 6,600 or 6,400—leaving 8,000 by year-end at 69% and a dip to 7,400 at 74%.

Worth noting for context: Kalshi filed stock index and copper perpetual futures with the CFTC this week. If those list, the hedging demand currently expressed through these Range ladders has a more natural home, and the open-interest picture on this page could change quickly.

• Whether the two crash contracts move. $1.5M on sub-5% strikes is stable right up until it isn't. Any real volume on either is the most informative thing this complex can produce.
• Kalshi's perpetual futures filing. Index perps would give this hedging flow a cleaner instrument. Watch whether year-ladder open interest starts to bleed once they list.
• The 123-to-1 daily-volume gap with Polymarket. Kalshi owns the long-dated index open interest; Polymarket owns the daily tape. That split has been widening.
• The 7,800 coin flip. $157,186 on a contract priced at exactly 50% with four months to run. It resolves one way or the other and somebody is very exposed.
• The year-high implied at 8,101 against Polymarket's 69% on 8,000. Those are close to consistent, which is reassuring—the two exchanges disagree about where the volume goes, not about the level.