Go beyond the level. Understand the why.

Gamma exposure, explained

Read modeled exposure beside price, with its limits in view.

A wall approached from below

SPYSep 10, 2026Historical

Put wall 760.00

5m candles · XNAS · recorded model

Blog · GEX levels3 min read

Reading call and put walls

Find exposure concentrations and watch how price approaches them.

1m candles · XNAS · recorded model

Above, then back below

Flip ≤1 DTE 716.60

Blog · Gamma exposure3 min read

What changes at the gamma flip?

Inspect a model’s sign change without turning it into an entry signal.

Where the session’s activity concentrated

Value area Outside value area

Completed session · XNAS minute-close estimate

Blog · Chart workflow4 min read

Read the volume profile

Find where trading activity concentrated, then put today’s price in context.

Two horizons. One session.

Flip ≤1 DTE 716.60Flip ≤7 DTE 718.05

15m closes · XNAS · recorded model

Blog · Chart workflow2 min read

Choose your expiry window

Compare the contracts behind each exposure view.

IWM context · ETF dollars

IWMSep 11, 2026Historical

Put wall 290.00

15m closes · XNAS · recorded model

Blog · Chart workflow2 min read

ETF context for futures traders

Read SPY beside ES and QQQ beside NQ without mixing price scales.

15m model delay · OI time unknown

SPYSep 10, 2026Historical

Model time ≠ candle time

Model built 7:01 AM ETFirst recorded 7:03 AM ET

Blog · Data & methodology2 min read

Check the data clocks

Separate price, candle, open-interest and model times before reading a level.

One wall. Repeated tests.

IWMSep 11, 2026Historical

Put wall 290.00

1m closes · XNAS · recorded model

Blog · GEX levels2 min read

A field guide to GEX levels

Read walls, flips and strike profiles in one chart.

XNAS prices · Tradier model

Model built 3:03 AM ETFirst recorded 3:08 AM ET

15m model delay · OI time unknown

Blog · Data & methodology2 min read

Choose an options data tool

Check coverage, clocks and model assumptions before subscribing.

Blog · Gamma exposure5 min read

Positive gamma vs negative gamma: what the sign assumes

What changes between a modeled long-gamma and short-gamma book, and why the sign rests on an assumption.

Blog · Gamma exposure5 min read

What 0DTE options do to gamma exposure

Why same-day contracts can dominate a nearest-expiry book, and how to compare it with wider windows.

Blog · Gamma exposure5 min read

How SPX and SPY gamma exposure differ

Compare the SPX index book with the SPY ETF book before you carry a level from one chart to the other.

Blog · GEX levels5 min read

What is a gamma squeeze?

What traders mean by a gamma squeeze, why open interest cannot confirm one, and what a GEX chart can show.

QQQ · 1,671 sessions · dashed line: a plain price · dots: call walls in force at 09:36

How often price reaches a wall

Distance sets how often.

How often price reaches a wall

Are walls reached more often than other prices the same distance away? On SPY and QQQ, 2018–2024, at four times of day, slightly less often: a wall added no boost.

REAL PRICES · REBUILT LEVELS · BACK-TESTED TRADES

The win-rate trap

Same entries. Only the target moves.

4 rules × 7 target settings · 9 stocks · 2018–2024

Weekly

The win-rate trap

A closer profit target raises the win rate. What it did to the average trade: four back-tested rules, nine stocks, 2018–2024.

What the stock paid anyway.

Beat the naive trade first

9 stocks · 2018–2024 · bar: share of five-session windows that ended higher · dashed line: half · price only

Weekly

Beat the naive trade first

Much of a rule’s average is what the stock paid anyway. Compare each rule with a naive trade in the same stocks first: two back-tested wall rules, 2018–2024.

A wall is recomputed as price moves.

How long does a wall last?

Call walls, SPY and QQQ · share still on the same strike after 1, 5, 10 and 21 sessions · rebuilt wall (solid) and the earlier nearest-expiry wall (dashed)

Weekly · Monthly

How long does a wall last?

On SPY and QQQ, May 2018 to December 2024, a call wall rebuilt at 09:36 was still on the same strike the next session 59% of the time, after five sessions 33%.

REAL PRICES · REBUILT LEVELS · BACK-TESTED TRADES

How many trades until you know?

Four times the trades halve the doubt.

11 measured 95% ranges · one rule, rebuilt at the 5-minute mark · gold line: ±3.6/√trades

Weekly · Monthly

How many trades until you know?

How many trades before an average can be told apart from luck? A rule of thumb worked on a call-wall breakout rebuilt at the 5-minute mark: about 1,000 trades for a small average, which is about 20 years at one trade a week.

REAL PRICES · BACK-TESTED TRADES

The best of 480 backtests

5 passed the pass mark. Then we adjusted for the number tried.

480 versions · 12 stocks · 2021–2024 · white: passed · red: failed · grey: under 30 trades

Weekly · Monthly

The best of 480 backtests

A count of the 480 back-tested rule versions behind the best-looking few, and a five-step routine, with spreadsheet formulas, to score any backtest.

A random line at a matched distance, for every level.

Map levels and random lines

1,161 symbol-sessions · 2023–2024 · bars: real lines per kind on the 10:00 ET map

What “held 75%” really measures

Rebuilt morning map levels held only slightly more often than random lines, and a level on the far side of the day’s move holds by definition. Recorded QQQ, SPY and IWM sessions, 2023–2024.

36 situations, each measured against random lines.

Thirty-six level tests

Call wall 6 · Put wall 6 · Daily flip 4 · Weekly flip 4 · Monthly flip 4 · Prior-day high 6 · Prior-day low 6 · 2018–2024

Blog · Setups & evidence14 min read

Thirty-six level tests, none passed every rule

Walls, flips and prior-day lines against random lines at the same distance: none of 36 situations passed every rule.

REAL PRICES · REBUILT LEVELS · BACK-TESTED TRADES

Is the monthly flip a floor?

Four situations at the flip, each counted.

Support fade146
Resistance fade157
Break down72
Break up52

SPY and QQQ · 2018–2020 · 427 recorded events at the monthly flip

Intraday · Monthly

Is the monthly flip a floor?

On SPY and QQQ, 2018–2020, a bounce from the monthly gamma flip did no better than a random line the same distance away, and the data make a floor lift above about +4 points unlikely.

The daily flip needs a same-day expiry.

When the daily flip is not drawn

Share of sessions with a daily flip at 09:35, by year

When the daily flip is not drawn

The daily flip is built from options that expire today, so a day with none has no line. How to tell that calendar gap from a chart problem.

Same stock, two price units.

A split is not a move

AAPL close, raw and adjusted, 10 sessions either side of Aug 31, 2020

When a split moves your level

AAPL’s raw close fell 74.2% on 31 August 2020 while its adjusted close rose 3.3%: a 4-for-1 split changes the unit, not the stock. Six corporate actions in 12 stocks, with their wall strikes.

Months with two different walls.

Monthly expiry Fridays measured

2018–2024 · solid: monthly sessions with two different walls · dashed: all monthly sessions

Intraday · Monthly

Does price end monthly expiry Friday near the walls?

Over monthly expiry Fridays from May 2018 to December 2024, we did not detect price finishing the last half hour nearer the closer call or put wall than a random line would.

80 monthly expiries, 70 Mondays and 78 Fridays to compare.

The Monday after monthly expiry

SPY and QQQ · 2018–2024 · counts, not dates · filled: a Monday after that could be kept · hollow: holiday or early close

Monthly

Monday after monthly expiry: calmer or wilder?

Does the Monday after monthly options expiry have a bigger or smaller range than other Mondays? A test on SPY and QQQ, 2018–2024, and how large a difference it could have missed.

78 month-ends · SPY and QQQ · before the closing cross

The last 15 minutes of month-end

Month-ends counted per year, May 2018 to December 2024 · minute prices, not levels

Monthly

Month-end’s last 15 minutes: bigger, direction unclear

SPY and QQQ, 78 month-ends, May 2018 to December 2024: the last 15 minutes before the closing cross moved farther than on ordinary days, and the test could not tell which way.

Where the day-1 walls and their mirror lines sat.

Do site walls beat a mirror line over a month?

SPY, the 21 sessions from Nov 1, 2024: the day-1 call and put walls and a mirror line for each. 80 months, 2018 to 2024.

Monthly

Do site walls beat a mirror line over a month?

Is a wall rebuilt at the 5-minute mark on a month’s first session reached any more or less often than a mirror line? On SPY and QQQ, May 2018 to December 2024, no difference was detected.

A session, cut into half hours.

Does the market drift at the same time every day?

SPY, Dec 31, 2024. 18 tickers × 13 half hours = 234 cells, 32,969 ticker-sessions, 2016 to 2024.

Does the market drift at the same time every day?

Averaged across 18 stocks and ETFs, September 2016 to December 2024, no half hour of the session drifted at any size the test could see. One stock in one half hour held up in both periods, before costs, and it is not shown to be a trade.

1,656 SPY sessions · 1,659 QQQ sessions · before the closing cross

The last half hour of the day

Sessions counted per year, May 2018 to December 2024 · solid: the two periods compared · minute prices, not levels

Last half hour’s share of the day: no change detected

SPY and QQQ, 2018 to 2019 against 2023 to 2024: no change detected in the last half hour’s share of the day’s price movement, and a test that could only see a change of about a fifth of that share or more.