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Options & FlowUpdated daily after close

SPY Options Open Interest: Dealer Walls, P/C Ratio & Gamma

Free SPY options open interest dashboard — the full SPY chain snapshotted each evening and synthesized into a daily positioning map: P/C OI across expiration horizons, near-spot strike concentrations, max pain, and modelled dealer gamma with an estimated flip level. Today's snapshot contains 12,730 listed option series across all strikes and expirations.

Today's reading

As of market close on October 19, 2026, SPY's all-expiration put/call open-interest ratio is 2.171 — a Defensive threshold band (72/100) and the 42th-percentile reading in this site's 105-snapshot record. The ≤7-day ratio is lower at 1.858 (Defensive), so the near-term book is less defensive than the full standing book. The P/C OI ratio fell 0.118 from the prior session. Max pain is $765 (-0.2% from spot $766.48). Modelled net dealer gamma is $9.73B, with spot 1.0% below the $774 model flip. The largest aggregated ≤7-day put and call concentrations around spot are $731 and $790. The series covers 105 daily snapshots since 2026-05-10.

Sources, methodology & freshnessFull SPY options chain snapshot (Polygon-compatible market-data API) · Daily snapshot after the cash close (~1:30 PM PT)Data as of 2026-10-19 · Open ↓
Source
Full SPY options chain snapshot (Polygon-compatible market-data API)
Methodology
Per-series OI / volume / Greeks aggregated by strike; max pain via minimum holder payout; gamma uses a disclosed simplified dealer-side convention
Updates
Daily snapshot after the cash close (~1:30 PM PT)Data as of 2026-10-19
Maintained & reviewed by Yuriy Matso — methodology shown on the page.
The answer · SPY options OI2026-10-19market close
DEFENSIVE
72/100

Put-heavy standing book under this page’s heuristic thresholds. It is not a bearish forecast.

All-expiration book
P/C 2.171Δ1d -0.118
42th percentile of 105 snapshots
Near-term book · ≤7 days
P/C 1.858
Defensive threshold band — materially lighter than All
Modelled dealer gamma
$9.73B
Estimated net long gamma · spot 1.0% below flip
Largest near-spot ≤7d concentrations
$731 ↔ $790
Put OI below spot ↔ call OI above spot; concentrations, not guaranteed bounds
SPY spot
$766.48
Max pain
$765 · -0.2%
Open contracts
17.70M

Gamma and “wall” reads are model estimates using a simplified dealer-side convention. They describe positioning and possible hedging pressure—not direction or hard support/resistance.

Interactive chartExplore the full SPY strike × expiration landscapeMove beyond a single strike profile and inspect open interest, volume, implied volatility and modelled dealer gamma across the entire options surface.Explore
01

Positioning across expirations

Snapshot: 2026-10-19 · captured 2026-10-19T20:55:38.673018+00:00. OI effective date: not separately supplied. Vendor reports open interest at the end of the last trading day; the response does not identify its effective date.

Expiration filter
Selects the detailed OI chart, max-pain, model flip and position tables below. The top answer and history remain anchored to All expirations for a consistent daily read.

The horizon split

The headline all-expiration book is Defensive at 2.171, while the ≤7-day book is Defensive at 1.858. The near-term and standing books carry a similar mix of puts and calls, so the headline ratio is not hiding a different near-term picture.

73% of all put OI expires beyond 30 days
1.069 ≤7-day P/C volume today
2.138 0DTE P/C open interest

P/C OI across expiration windows

Each row is cumulative: ≤7 days includes 0DTE. Click a bar to change the detailed view below.

Selected · All expirations
Greedy <1.10Balanced 1.10–1.70Defensive 1.70–2.50Stress ≥2.50Heuristic bands, not directional forecasts.
02

OI distribution

OI Distribution by Strike

Open interest aggregated by strike within ±25% of spot. Dashed lines mark today's spot, max pain, and the modelled gamma-flip estimate.

Model Gamma / 1% move $9.73B (estimated net long)Call Vol 5.74MPut Vol 6.76M

Selected-view answer · All expirations

SPY $766.48
Positioning balance
P/C OI 2.171
Defensive band · P/C volume 1.178
Reference levels
$765 / $774
Max pain -0.2% · model flip +1.0%
Near-spot OI concentrations
$750 ↔ $800
Largest put OI below spot ↔ call OI above spot, aggregated by strike within ±5%

Model gamma per 1% spot move is $9.73B (net long under the model). The concentrations above are landmarks where hedging may matter; they are not price targets or guaranteed support/resistance.

Fixed vendor IV, Black-Scholes with zero rates and dividends; short calls / long puts assumed; dollars per 1% spot move. Excludes expired EOD options; nearest sign crossing within 50–150% of spot, at least 80% active OI with IV. The calculation uses the whole selected expiry bucket; the chart shows only nearby strikes. IV covers 100% of unexpired OI.

03

Dealer walls and large positions

These tables rank individual strike × expiration series by open interest. They reveal where positions are concentrated, but OI alone does not identify who owns the contracts or whether a trade is outright, hedged, or part of a spread. Near-spot rows may become hedging landmarks; far-tail rows describe distant positioning, not immediate support or resistance.

Largest Individual Put Positions

Ranked by OI in one strike × expiration series. Distance from spot determines present relevance.

Strike% from SpotOIVolExpDTE
$480-37.4%far / tail310,933112026-12-1860d
$500-34.8%far / tail309,2075,4272026-11-2032d
$510-33.5%far / tail200,40712026-11-2032d
$620-19.1%far / tail165,2578142026-11-2032d
$350-54.3%far / tail157,68952026-12-1860d
$610-20.4%far / tail157,4842262026-12-1860d
$520-32.2%far / tail153,0751632026-11-2032d
$380-50.4%far / tail150,947112026-11-2032d
$570-25.6%far / tail150,651102026-10-3011d
$700-8.7%far / tail130,1146572027-03-19151d
Largest Individual Call Positions

Ranked by OI in one strike × expiration series. Distance from spot determines present relevance.

Strike% from SpotOIVolExpDTE
$810+5.7%nearby79,6591,3602026-12-1860d
$800+4.4%nearby53,7615,3322026-11-2032d
$800+4.4%nearby51,2184,0172026-12-1860d
$800+4.4%nearby48,8863,5072026-10-3011d
$810+5.7%nearby43,4481,6882026-11-2032d
$834+8.8%far / tail40,382852026-10-3011d
$820+7.0%nearby38,3302,2692026-11-2032d
$790+3.1%nearby36,3803,6752026-10-234d
$830+8.3%far / tail34,1414512026-12-1860d
$770+0.5%near spot33,8323122026-12-1860d
04

P/C history

P/C OI Ratio History

Daily all-expiration P/C OI ratio with SPY overlay and heuristic threshold bands. Historical chains aren't served by the source API, so this record accumulates forward from 2026-05-10.

Current2.171Record median2.232Percentile42th
P/C OI ratio (left) SPY price (right)history accumulates daily — meaningful around 30 sessions in

105 daily snapshots captured so far.

How SPY Options Open Interest Works

  1. 1
    Pull the full SPY options chain after market close
    Each trading day after the cash close, we snapshot the entire SPY options chain — every listed strike × expiration series with volume, open interest, implied volatility, and Greeks (delta, gamma). A typical snapshot contains more than 12,000 listed option series and millions of open contracts.
  2. 2
    Compute put/call ratios and classify the regime
    Total put OI ÷ total call OI is the headline positioning read. This page applies fixed heuristic bands: <1.10 = Greedy, 1.10–1.70 = Balanced, 1.70–2.50 = Defensive, and ≥2.50 = Stress. The live page also shows today’s percentile inside our accumulating snapshot record; neither the label nor percentile predicts direction.
  3. 3
    Separate near-spot concentrations from far-tail positions
    The detailed tables rank individual strike × expiration series by open interest and label their distance from spot. Separately, the current-view answer aggregates OI by strike and identifies the largest put concentration below spot and call concentration above spot within ±5%. OI does not reveal who holds a contract or whether it belongs to a spread, so these are landmarks—not guaranteed support or resistance.
  4. 4
    Calculate max pain — the pin strike
    Max pain is the candidate strike that minimizes the aggregate intrinsic-value payout implied by the selected book. Traders sometimes use it as an expiration-pinning reference, but it is not a forecast and the all-expiration calculation blends contracts with very different maturities.
  5. 5
    Build the dealer gamma curve and zero-gamma flip
    For each strike we compute dollar gamma (OI × gamma × 100 × spot² × 0.01) under a simplifying convention: calls count as negative dealer gamma and puts as positive. The nearest sign crossing of total gamma repriced across hypothetical spot prices becomes the modelled flip. Because public OI does not reveal customer/dealer ownership and the calculation holds IV fixed with zero rates and dividends, this is a transparent scenario estimate; the dealer inventory itself is unobserved.
  6. 6
    Accumulate forward — P/C ratio history
    The source API does not provide this historical chain series, so we build the P/C record forward by appending each daily snapshot. The page states the exact start date and sample count, and compares today only with that available record.
  7. 7
    Pre-bucket by expiration so users can slice the picture
    The same chain is aggregated four times: all expirations (the full book, today out to LEAPS), ≤30 days (the next month), ≤7 days (this week's expiries), and 0DTE (today only). The detailed P/C ratio, max-pain, model flip, OI chart, and position tables recompute when you switch buckets. The top daily answer and history intentionally stay anchored to all expirations, so the headline does not change as you explore.

Who Uses SPY Options Open Interest

Day Traders
Use the near-spot put and call concentrations as landmarks to watch, especially in the ≤7-day and 0DTE views. Confirm any reaction in price and volume rather than assuming the levels will hold.
Swing Traders
Compare the all-expiration book with ≤30-day and ≤7-day windows. A divergence distinguishes longer-dated positioning, which may include portfolio hedges, from the current short-term book more clearly than the headline ratio alone.
Volatility Traders
Track the modelled gamma sign and flip across expiration windows as a possible hedging-pressure map. Treat it as a sensitivity analysis whose result depends on the stated dealer-side convention. It offers no direct view of dealer books.
Long-Term Investors
Use the accumulating P/C history to compare today with this site’s available record. The page shows the start date, median and percentile so a short sample is never presented as a multi-year backtest.

Pro Tips

01
Trust the strike over the expiration date alone
A large position near spot and expiry has a different risk profile from deep-OTM insurance months away. Always read strike distance, days to expiry and current gamma alongside the raw OI count.
02
Walls far from spot are tail positions, not pin candidates
Large positions 20–30% from spot are not immediate price landmarks and may be insurance, spreads, speculation or stale inventory. That is why the page separately computes the largest aggregated concentrations within ±5% of spot.
03
Re-check the model after high-volume sessions
Re-check the model after large-volume sessions because open positions and Greeks can reshape the estimate. A moving flip is evidence that the input book changed; it is not proof that dealers will defend or accelerate a particular price.
04
P/C OI > P/C volume is the structural signal
Volume is today’s activity; OI is the outstanding book. Comparing their put/call ratios helps distinguish a put-heavy inventory from put-heavy current trading, but volume alone cannot tell whether positions were opened, closed, bought or sold.
05
Max pain matters most in the last week before expiry
If you use max pain as an expiration reference, prefer the ≤7-day or 0DTE calculation to the all-expiration number. Even near expiry, treat pinning as a hypothesis to confirm in the tape—not a mechanical force.
06
Treat the modelled gamma sign as scenario context
Under this page’s simplifying convention, negative modelled gamma corresponds to an amplifying hedge response and positive gamma to a dampening response. Public OI cannot verify actual dealer ownership, so use the sign as scenario context and keep the assumption attached.

Common Issues & Solutions

The history chart looks empty / sparse▾
No free source serves historical chain snapshots, so we build the P/C ratio time series forward starting when we first ran the daily fetch. Give it a few weeks. After ~30 sessions the chart becomes meaningful for comparing today to recent norms.
Today's data shows a stale timestamp▾
We snapshot the chain after the cash close so OI and volume reflect end-of-day numbers. If you're viewing during market hours, the data is from the prior close — open interest itself is only updated overnight by the OCC anyway.
Why is my "top wall" not where price is heading?▾
Walls are *concentrations*, not forecasts. A large put position only shows that many contracts remain open at one strike and expiration; it does not identify the owners, their direction, or their hedges. Use it as a map reference alongside price and volume, not as a target or a level that must hold.
The zero-gamma flip is far from spot — what does that mean?▾
It means the nearest sign crossing of repriced total gamma under this model is far from the current price, so it is not an immediate landmark. It does not prove the actual dealer book is firmly long or short gamma; public OI lacks ownership and trade-direction data.

Frequently Asked Questions

What is options open interest?▾
Open interest is the total number of option contracts that are currently outstanding for a given strike and expiration. It is updated overnight, while volume measures how many contracts traded during the session. Concentrated OI shows where positions exist, but not whether customers or dealers are long, short, hedged, or using spreads.
What is the put/call ratio and why does it matter?▾
The put/call ratio is total put activity divided by total call activity. We track volume (today’s trading) and OI (the outstanding book) separately, then compare cumulative expiration windows. More put OI can reflect hedging, speculation or spreads; it is positioning context and forecasts no direction. The page shows both fixed heuristic bands and today’s percentile inside our stated snapshot record.
What is max pain?▾
Max pain is the candidate strike that minimizes aggregate intrinsic-value payout to holders if the selected option book expired there. Traders use it as a possible expiration-pinning reference, but OI does not reveal writers’ hedges and the result is not a price forecast. Short-window calculations are more internally coherent than blending expirations across the full book.
What are dealer walls / OI walls?▾
A wall is shorthand for concentrated open interest at a strike. Such concentrations may become hedging landmarks, especially near spot and expiry, but public OI does not reveal whether customers or dealers are long, short, hedged or spread. This page therefore calls them concentrations, separates near-spot aggregated strikes from far-tail individual positions, and does not promise support or resistance.
What is the zero-gamma flip level?▾
For each strike we compute dollar gamma (OI × gamma × 100 × spot² × 0.01) under a simplifying convention: calls count as negative dealer gamma and puts as positive. The nearest sign crossing of repriced total gamma across hypothetical spot prices is shown as the model flip. Public OI does not reveal dealer ownership, and IV is held fixed with zero rates and dividends, so the level is a transparent scenario estimate—not an observed dealer position.
How do I read the regime score?▾
The score maps fixed P/C OI bands onto 0–100: 0–30 = Greedy (<1.10), 30–55 = Balanced (1.10–1.70), 55–85 = Defensive (1.70–2.50), and 85–100 = Stress (≥2.50). These are transparent heuristic labels. Use the on-page record percentile and expiration comparison for context rather than treating the score as a probability or trade signal.
Where does the data come from?▾
A daily snapshot of the full SPY options chain from a Polygon-compatible market-data API — every strike × every expiration with volume, open interest, implied volatility, and Greeks. We snapshot once daily after the cash close so the numbers reflect end-of-day positioning.
Why does the history look short?▾
Historical chain snapshots are not served by this page's source API. We therefore build the time series forward by saving each daily snapshot, and state the exact start date and sample count beside the chart.
Can I see this for QQQ or other ETFs?▾
Today the page is SPY-only. The underlying pipeline can process other liquid US options symbols, but each additional market would need its own scheduled snapshot history, validation, and page treatment.
How is dealer gamma calculated?▾
For each option series, dollar gamma = open interest × gamma × 100 × spot² × 0.01. This model counts call gamma as negative and put gamma as positive, then aggregates by strike; the model flip is the nearest sign crossing after repricing the whole selected book across hypothetical spot prices. It is assumption-driven because the public chain does not identify customer/dealer ownership, opening versus closing trades, or spread relationships.
What does the Expiration filter do?▾
The toggle selects four pre-computed cumulative views of the same chain: All expirations, ≤30 days, ≤7 days, and 0DTE. The selected-view answer, OI distribution, P/C ratio, max pain, model flip and large-position tables update together. The top daily answer and P/C history remain anchored to All expirations for a consistent comparison. Because the windows are cumulative, ≤7 days includes 0DTE.
Why does the P/C ratio change so much between expiration buckets?▾
Open interest accumulates differently across maturities. The all-expiration book includes longer-dated positions and LEAPS, while ≤7-day and 0DTE views isolate much shorter-lived positioning. A put-heavy full book alongside a lighter near-term book means the maturity mix differs; it does not identify the strategies behind those contracts or reveal whether SPY will rise or fall.
Should I trust max pain more for short-dated or longer-dated expiries?▾
The ≤7-day or 0DTE calculation is more internally coherent as an expiration reference because most included contracts expire together soon. The all-expiration result blends many maturities and should be treated as a structural summary. Neither version is a forecast, and any pinning thesis should be confirmed in price and volume.

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