ILMN Market Structure
Illumina, Inc. (ILMN) operates in the Healthcare sector, specifically the Medical - Diagnostics & Research industry, with a market capitalization near $21.94B, listed on NASDAQ, employing roughly 8,970 people, carrying a beta of 1.42 to the broader market. Illumina, Inc. Led by Jacob Thaysen, public since 2000-07-28.
Market structure data reveals where a stock trades across exchanges, dark pools, and alternative trading systems. Understanding off-exchange activity helps identify institutional trading patterns and liquidity dynamics.
- Latest Week Ending
- 2026-04-20
- Weekly OTC Shares
- 781.5K
- Weekly OTC Trades
- 14.9K
- 12-Week Total Shares
- 13.9M
- Avg Trade Size (12-Week)
- 83 shares
How Single-Name Off-Exchange Volume Affects Options
For single-name equities, persistent off-exchange volume concentrations can flag institutional positioning - large blocks arranged through ATS venues to avoid lit-market impact, or correlation-arbitrage flow from sector rotation. The flow doesn't directly move the lit-market price (it prints at the ATS) but it changes the inventory position of the institutional counterparty, which then drives subsequent lit-market flow. Compare the off-exchange volume series above with ILMN's gamma exposure and options volume history to see whether unusual dark-pool activity coincides with rebalancing in the options book.
Showing 12 weeks of off-exchange trading data for Illumina, Inc..
Learn how market structure is reported and how to read the data →
Frequently asked ILMN market structure questions
- What is the current ILMN off-exchange volume?
- For the week ending Apr 20, 2026, Illumina, Inc. (ILMN) recorded 781.5K shares across 14.9K trades (average trade size 52 shares). The 12-week cumulative total is 13.9M shares.
- What does ILMN off-exchange volume mean for traders?
- Off-exchange volume on a single-name equity reflects institutional block trades arranged through alternative trading systems (ATS) for liquidity rather than information reasons. Persistent ATS volume on a name can signal large institutional repositioning; the lit-market price impact lags the off-exchange print by hours to days as the institutional counterparty hedges or unwinds.
- How is ILMN market-structure data sourced?
- Weekly off-exchange volume figures come from FINRA's OTC Transparency reporting, which captures trades executed through FINRA-member off-exchange venues including ATSs and member firm internalization desks. FINRA publishes the data with a two-week lag (current-week-minus-two-weeks) for ATS-specific volume and weekly aggregate volume; the totals here aggregate all member firm reporting. Trades cleared via the listed-exchange auction are NOT included; the figure reflects only the off-exchange portion of total volume.