Options Analytics

NDX vs SPX Weekly Options

Comparative ATM IV, IV−RV spread, put skew and term structure for QQQ (NDX proxy) vs SPY (SPX proxy)

ETF proxies used: QQQ ↔ NDX, SPY ↔ SPXLast updated: 2026-05-29T21:20:42.407Z

Headline KPIs

Quick comparison of QQQ vs SPY weekly options: ATM IV, put skew and IV−RV spread.

Avg Weekly ATM IV

Near-term weekly implied vol at-the-money.

QQQ

28.40%

QQQ +7.70pp

SPY

20.70%

Avg Weekly Put Skew (−25d − ATM)

Put skew: IV(put −25 delta) minus IV(ATM).

QQQ

2.10%

QQQ +0.80pp

SPY

1.30%

Avg IV − RV (Spread)

Difference between implied and realized over option life.

QQQ

4.80%

QQQ +1.70pp

SPY

3.10%

Volatility Charts

Weekly ATM IV

QQQ vs SPY — 6-month window

QQQSPY

IV − RV Spread

QQQ vs SPY — 6-month window

QQQSPY

Term Structure Analysis

Term Structure — Buckets

Average implied volatility by tenor bucket

Tenor	QQQ	SPY	Spread
5-9 DTE	27.80%	20.30%	+7.50pp
10-14 DTE	26.40%	19.90%	+6.50pp
25-35 DTE	25.10%	19.20%	+5.90pp

Methodology & Data

Data Source

yfinance via a backend service. ETF options used as proxies for index options (QQQ ≈ NDX, SPY ≈ SPX).

Proxies

ETF options used as stand-ins for index options. Differences may exist due to dividends, trading hours, microstructure, and tax treatment.

Weekly Selection

Focus on expirations within 5–14 DTE. Excludes standard monthlies to focus on "pure weeklies".

Skew Definitions

Put skew = IV(put −25d) − IV(ATM). Risk reversal = IV(call +25d) − IV(put −25d).

Realized Volatility

Annualized std of log returns over the option life (≈ sqrt(252)). Aligns realized windows to match each weekly expiry cohort.

Term Structure

Compare average IV by tenor buckets (e.g., 5–9 DTE vs 25–35 DTE). Bucket expirations by tenor for comparison.

Important Limitations

ETF vs index nuances; yfinance IV completeness/accuracy; holidays; stale quotes. Values shown here are sample data for UI scaffolding.