Open Interest Monitor – 2 September 2025

Data through market close 1 September 2025

What is the Open Interest Monitor?

The Open Interest Monitor tracks which options have the highest total open interest across stocks, ETFs, and indices. It helps highlight where liquidity is deepest, where institutional activity may be concentrated, and which themes are drawing the most attention in the options market. Whether you're looking for trading ideas, better execution, or insights into market sentiment, open interest offers a valuable lens.

Note: This edition covers options on US-listed underlyings only. 

Top 20 open interest leaders (as of 1 September 2025)

This table shows the 20 listed options with the highest total open interest, combining calls and puts. Open interest data reflects active outstanding contracts and offers insights into market liquidity, sentiment, and positioning.

What the columns mean (short version):

What traders can take away

The strongest build-up in new positions over the past month came in QQQ, EEM, TLT, AAPL and TSLA. This shows investors are not only focused on big technology, but also on emerging markets and bonds. TLT’s jump points to attention on interest rates, while EEM shows more global appetite beyond the US.

Volatility is low across almost all of the top names. Even the highest IV ranks are under 10%, meaning option prices are cheap compared to the past year. For buyers, this can be an opportunity to get exposure at lower cost. For sellers, it means less premium to collect. The low-volatility environment helps keep markets calm, but also leaves little buffer if surprises occur.

Put/call ratios reveal where investors are defensive. Small caps (IWM) and high-yield bonds (HYG) have more puts than calls, suggesting portfolio protection is being built there. In contrast, SPY looks balanced and single stocks like NVDA and AMZN lean more to calls. Volume remains deepest in SPY, NVDA and QQQ, confirming where liquidity and institutional focus sit.

Overall, open interest is both concentrated and broad. ETFs dominate the leaderboard, showing preference for index-level exposure, but large tech names keep drawing focused attention.

A few observations

The most striking feature is how low implied volatility is across the board. Option markets are pricing calm conditions, with little sign of fear. That can last for a while, but it also means any shock could feel sharper.

Defensive hedging is visible in small caps and credit ETFs, even while large tech flows look constructive. Rates-related ETFs like TLT and HYG stand out, showing traders are attentive to both bond yields and credit spreads.

Beyond megacap tech, flows into EEM and financial ETFs like XLF and banks (BAC, JPM) show interest in diversifying trades. Still, the semiconductor complex (NVDA, INTC, AMD) remains central.

Finally, it is worth noting that some of the open interest changes can be due to rolling positions from one expiry to another. This can increase OI without necessarily changing investor direction.

Conclusion

Options positioning remains concentrated in indices, large tech, and bond ETFs. Nvidia leads in absolute open interest, while QQQ, EEM and TLT saw the fastest growth. Low volatility across the board sets the tone: markets are calm, options are cheap, but risks can surface quickly. Defensive hedging in small caps and credit contrasts with ongoing enthusiasm for tech and index exposure.

Glossary

• Ticker: the exchange-listed symbol for the underlying stock, ETF, or index. Indices are noted with a $ prefix in general use, but we map them to specific exchange codes in the ticker string.

• Name: the company or ETF name associated with the ticker. ETFs typically describe their focus, such as “S&P 500” or “20+ Year Treasury Bonds.”

• Last: The last traded price of the underlying asset (stock, ETF, or index). This gives a reference point for where the asset currently trades and helps identify how close it is to key strike levels in the option chain.

• IV Rank (%): Implied Volatility Rank (IV Rank) shows where current implied volatility sits relative to the past 12 months. A reading of 0% means IV is at its lowest point of the year; 100% means it's at the highest. Higher IV Rank suggests options are more expensive compared to recent history, which may favour premium-selling strategies.

• Total Open Interest (Total OI): This is the total number of open option contracts across both calls and puts for the underlying. It represents outstanding positions that have not yet been closed or exercised. High OI is often associated with deep liquidity and significant institutional interest.

• 1M OI % Change: Shows how much total open interest has changed over the past month. A rising figure can point to fresh positioning or increased speculation, while a falling number may indicate closed-out trades or reduced interest in the underlying.

• Options Volume: The number of option contracts traded during the most recent session. High volume relative to open interest may suggest new trades are being initiated. Sudden spikes often coincide with market-moving news or upcoming events.

• Put/Call Volume Ratio (P/C Vol): This ratio compares the volume of puts traded to calls on the same day. A ratio above 1.0 implies more puts were traded (often for downside protection), while a value below 1.0 shows call-heavy flow (often speculative or bullish). Extreme readings can highlight skewed sentiment or potential contrarian signals.