Merck & Co., Inc. (MRK) Open Interest History
Open interest tracks the total number of outstanding options contracts. Rising OI alongside price moves can indicate growing commitment to the trend; declining OI suggests positions are being closed.
Merck & Co., Inc. (MRK) operates in the Healthcare sector, specifically the Drug Manufacturers - General industry, with a market capitalization near $359.09B, listed on NYSE, employing roughly 74,000 people, carrying a beta of 0.23 to the broader market. Merck & Co. Led by Robert Davis, public since 1978-01-13.
Snapshot as of Sep 30, 2026.
- Spot Price
- $145.54
- Call OI
- 271.7K
- Put OI
- 220.2K
- Total OI
- 492.0K
- Put/Call Ratio
- 0.30
As of Sep 30, 2026, Merck & Co., Inc. (MRK) has 492.0K total contracts outstanding across all expirations. Put/call OI ratio is 0.81 (balanced positioning). Open interest reflects accumulated positions from prior sessions; persistent growth indicates sustained directional or hedging interest, while sharp drops typically mean post-expiration clean-up.
How MRK open interest history Data Feeds Strategy Selection
Strategy selection on Merck & Co., Inc. options does not derive from any single metric in isolation. The open interest history view above sits inside a broader read: ATM IV currently sits at 37.1% and dealer gamma exposure is positive, so dealer hedging is mechanically mean-reverting. Combine the open interest history data here with the volatility-skew surface, dealer-gamma exposure, max-pain level, and upcoming-events calendar to build a positioning thesis. Risk-defined structures (credit spreads, debit spreads, iron condors) are usually safer than naked positions while the regime is uncertain; the data on this page anchors the inputs but does not by itself constitute a trade thesis.
How to read the MRK open-interest data
The open-interest time-series above tracks the total Merck & Co., Inc. options inventory outstanding day by day. OI is a stock measure - the cumulative position count - so trends flag accumulating or distributing positioning. Current put/call ratio is 0.30, call-heavy - speculative or bullish positioning dominates. Total call OI of 271.7K versus put OI of 220.2K gives a put/call OI ratio of 0.81 - structurally a slower-moving signal than the volume-based ratio.
MRK flow vs positioning
Volume tells you what flows happened today; OI tells you what positions accumulated. Both can move in opposite directions: rising volume with falling OI means contracts are being closed (covering); rising volume with rising OI means new positions are being opened. The combination matters more than either alone for reading sentiment. Combined with the current positive dealer-gamma regime, large OI clusters tend to act as price magnets through expiration cycles.
Using MRK OI/volume data alongside other surfaces
Per-strike OI is the input to dealer-gamma calculations: strikes with elevated call OI generate gamma walls that dealers must hedge into as spot approaches them. The gamma-exposure page combines this distribution with the dealers' assumed-long-gamma assumption to project hedge flow. Volume cross-checks recent positioning shifts in the chain that haven't yet shown up in cumulative OI. Pair both with the term-structure view on the volatility page to determine whether the activity is concentrated in near-dated event hedging or longer-dated structural positioning. Front-month expiration for MRK sits at 30 days, so near-dated volume currently dominates the flow reading.
Learn how open interest is reported and how to read the data →
Daily open-interest history for MRK options over the last ~42 trading days. Each row reflects the end-of-day total OI summed across all listed strikes and expirations.
Most recent 15 trading days (descending). Older history appears in the chart above.
| Date | Call OI | Put OI | Total OI | P/C OI |
|---|---|---|---|---|
| Sep 30, 2026 | 271.7K | 220.2K | 492.0K | 0.81 |
| Sep 29, 2026 | 270.8K | 216.1K | 486.9K | 0.80 |
| Sep 28, 2026 | 267.8K | 214.3K | 482.2K | 0.80 |
| Sep 25, 2026 | 278.2K | 218.4K | 496.6K | 0.78 |
| Sep 24, 2026 | 272.8K | 214.5K | 487.3K | 0.79 |
| Sep 23, 2026 | 257.1K | 209.3K | 466.5K | 0.81 |
| Sep 22, 2026 | 250.4K | 206.2K | 456.6K | 0.82 |
| Sep 21, 2026 | 240.4K | 202.4K | 442.8K | 0.84 |
| Sep 18, 2026 | 309.9K | 260.8K | 570.7K | 0.84 |
| Sep 17, 2026 | 306.7K | 256.1K | 562.8K | 0.84 |
| Sep 16, 2026 | 306.3K | 254.6K | 560.9K | 0.83 |
| Sep 15, 2026 | 295.6K | 253.2K | 548.7K | 0.86 |
| Sep 14, 2026 | 340.3K | 248.9K | 589.2K | 0.73 |
| Sep 11, 2026 | 341.2K | 252.9K | 594.1K | 0.74 |
| Sep 10, 2026 | 338.9K | 251.9K | 590.8K | 0.74 |
MRK highest open-interest contracts
| Type | Strike | Expiration | Volume | OI | IV | Bid | Ask |
|---|---|---|---|---|---|---|---|
| CALL | $160.00 | Oct 30, 2026 | 2.4K | 135 | 36.0% | $1.75 | $1.90 |
Top 1 contracts from the institutional-grade nightly options scan; ranked by oi within the broader S&P 500/400/600 + ETF universe.
Frequently asked MRK open interest history questions
- What is the current MRK options open interest?
- As of Sep 30, 2026, Merck & Co., Inc. (MRK) has 492.0K total contracts outstanding across all listed expirations, split as 271.7K calls and 220.2K puts. Open interest reflects accumulated positions from prior trading sessions; it does not include today's volume until end-of-day reconciliation.
- What is the MRK put/call open interest ratio?
- Put/call OI ratio of 0.81 is balanced.
- What does MRK open interest tell traders?
- Persistent OI growth indicates sustained directional or hedging interest; sharp drops typically mean post-expiration position cleanup. Heavy OI concentrations at specific strikes act as support and resistance levels because dealer hedging amplifies near those strikes - the gamma profile of the dealer book is concentrated there. Comparing today's volume to standing OI separates opening flow from closing flow.