Top Whale Tickers in September 2026: Where Insider Flow Is Loudest

Top whale tickers in early September 2026 still skew toward insider distribution, not open-market accumulation. In the last 14 days through September 6, 2026, ProBors whale leaderboards show CRWD (CrowdStrike) at 122 whale-class prints with zero buys, while CRNX (Crinetics Pharmaceuticals) ranks second by print count with about $343 million in net reported value—almost entirely code D dispositions, not code S sales. SE (Sea Ltd) and STX (Seagate) round out the loudest names by frequency and reported value. This guide maps the September leaderboard, a five-step triage framework for sell-heavy boards, recent large Form 4 filings worth a second look, and what leaderboard volume does not prove. It is research context, not investment advice.

Why the September 2026 whale board looks different from August

Whale activity is a leaderboard of large Form 4 prints ranked by frequency and reported value—not a sentiment index. Three shifts stand out in the current window:

• CrowdStrike replaces CoreWeave at the top of the 14-day print-count board. CRWD shows 122 whale-class rows and 122 open-market sales with zero purchases, while CRWV drops to 65 prints in the same window—still loud, but no longer the frequency leader.
• Crinetics dominates by reported value through disposition codes. CRNX carries 99 prints and about −$343 million in net reported value, yet the buy/sell split shows zero code S sales. ProBors indexes code D disposition rows from multiple officers on September 1, 2026—different economic language than discretionary open-market selling.
• Open-market purchases at whale scale remain scarce. The freshest September batch includes a notable LILA open-market purchase cluster, but mega-cap leaderboards like CRWD and SE still show zero buys across the 14-day window.

A ticker with triple-digit prints and zero buys tells a different research story than a name with large disposition volume and mixed codes. Start with the board, then drill into individual rows and SEC transaction codes.

14-day whale leaderboard (as of September 6, 2026)

The table below reflects ProBors whale activity over the last 14 days as of September 6, 2026. Print counts include large Form 4 rows indexed in the platform; net reported value sums directionally (sales and dispositions show as negative).

Over 30 days, CRWV still leads by print count (363 rows, zero buys, about −$3.94 billion in net reported value), followed by STX (256 prints, about −$97.4 million) and APPF (251 prints). The 30-day view confirms sustained post-IPO and high-growth distribution cycles—not a one-week spike tied to a single earnings date.

Note on mixed codes: CRNX, PMTS, and LEG can show large net values with zero code S sales in the buy/sell split because disposition (D), conversion, and other Form 4 codes also flow through whale feeds. Always open the underlying filing before treating a leaderboard rank as a bearish signal.

A five-step triage framework for loud whale tickers

Use the same checklist when a ticker tops the September board so tax withholding rows and disposition codes do not masquerade as discretionary flow.

1. Confirm the SEC transaction code

Open-market sales use code S; open-market purchases use code P. Grants (A), dispositions (D), conversions (C), and option exercises (M, X) are different economic events. ProBors shows the code and trade type on each whale row—filter here before reacting to dollar size.

2. Compare print count to open-market direction

A ticker can show hundreds of whale-class rows while buys stay at zero. That pattern on CRWD or SE means the story is distribution volume, not a hidden accumulation signal. Cross-check whether your row is code S in a sell-heavy name—or code D on CRNX, where the economic event may be a planned disposition rather than a discretionary sale.

3. Measure filing lag in calendar days

Form 4 is generally due within two business days after the transaction. A one-day lag on a September 3 trade filed September 4 is routine. Same-day filing on a large sale is also common. Longer gaps deserve a footnote read on SEC EDGAR.

4. Read signal scores as a sort key—not a verdict

ProBors signal scores weigh size, role, timing, and pattern history. A score of 8 on a multi-million-dollar disposition flags attention but does not prove bearish intent—it may reflect a vesting event paired with a planned sale. A score of 0 on a large sale can still be economically meaningful; it often means the row matches that insider's typical pattern. Sort by signal after filtering codes. For scoring details, see how ProBors trade signal scores work.

5. Cross-check chart and congressional context

Open the ticker workspace on ProBors: review price reaction since the trade date, any congressional markers, and whether the AI summary flags earnings or lock-up events. Whale flow plus politician activity on the same name is a stronger research prompt than either feed alone.

Recent filings worth a second look

The table below shows deduplicated whale rows from ProBors as of September 6, 2026, filed in the first week of September. Values are as reported in the platform; lag is calendar days between trade date and filing date.

How to read this snapshot without overfitting:

• NMIH is the largest single row in this batch—a same-day code S sale with a signal score of 0, meaning it matches the insider's historical pattern despite seven-figure size.
• LILA stands out as a rare open-market Purchase in a week dominated by sales. De Angoitia Alfonso filed multiple buy lines across August 31 and September 2, 2026—worth reading as one cluster, not isolated prints.
• STX Mosley William D. filed 26 code S lines on September 1, 2026 totaling about $24.5 million across tranches; the row above is the largest single print with a two-day filing lag.
• CRWD CEO Kurtz George filed 11 code S lines on September 3, 2026 totaling about $2.1 million—routine cadence on a name with 122 whale-class prints in 14 days, not a one-off event.

How to research whale tickers on ProBors

1. Open the Whales tab from the dashboard and sort by filing date (newest first).
2. Click Top tickers and toggle between 14-day and 30-day windows to see whether flow is sustained or spiking.
3. Filter by ticker when a name like CRWD or CRNX hits your watchlist.
4. Open a row to read transaction code, insider title, signal score, and footnote context.
5. Jump to the Market workspace for the same ticker to overlay price action and congressional markers.
6. Add tickers with recurring whale prints to a watchlist if you want alerts on the next filing—not on live price.

For tab navigation details, see the ProBors Whales tab guide. For the full triage checklist, see how to triage whale transactions on ProBors.

What this whale data does not prove

A sell-heavy whale leaderboard does not prove:

• That insiders traded on material non-public information
• That a ticker will fall because officers sold shares or filed dispositions
• Exact share counts or post-trade holdings (Form 4 value fields are as reported, not always full position snapshots)
• That every code S row is discretionary—many reflect plans, tax events, or fund rebalancing
• That zero buys on a leaderboard ticker means no insider interest (smaller purchases below whale thresholds may exist elsewhere in Form 4 data)
• That code D disposition volume on CRNX equals bearish insider sentiment—it may reflect vesting, plan language, or corporate actions

Insider selling and disposition activity is often routine. The research value is prioritization: which tickers deserve a footnote read, a chart check, and a second pass against the original SEC filing.

FAQ

What counts as a "whale" transaction on ProBors?

ProBors surfaces large Form 4 filings that meet size thresholds for the Whales feed—typically high-dollar open-market prints and other reportable rows that stand out from routine compensation activity. The exact cutoff is applied during ingestion; use transaction code and reported value together, not size alone.

Why does CRNX rank high with zero open-market sales?

CRNX shows 99 whale-class prints and about −$343 million in net reported value, but the buy/sell split shows zero code S rows. ProBors indexes code D disposition filings from multiple officers on September 1, 2026. Disposition codes reflect a different economic event than discretionary open-market selling—open the filing before treating the rank as a bearish signal.

Why do so many top whale tickers show zero buys?

Post-IPO and high-growth names often see concentrated insider and early-investor sales as lock-ups expire and compensation vests. In a sell-heavy cycle, the leaderboard reflects distribution volume across many filers—not a market-wide bearish signal.

How is September 2026 different from August on the whale board?

CRWD now leads the 14-day print-count board where CRWV and NET dominated in August. CRNX is new to the top ten by reported value. STX and UTHR remain active, but EA and DRI have rotated off the current 14-day frequency leaders. The overall sell-heavy shape persists; the specific names rotating through the top ten are what changed.

Should I short a stock because it tops the whale leaderboard?

No. Leaderboard volume is a research queue, not a trading signal. Verify each row on EDGAR, read footnotes for 10b5-1 plans, and treat the data as disclosure context. This is research context, not investment advice.

How often does ProBors refresh whale data?

Form 4 ingestion runs on a regular schedule. Check probors.com/status for the latest SEC Form 4 / Whales source health before citing rows in notes or publications.

Track whale flow on ProBors

Browse top tickers, filter Form 4 whales by signal score, and cross-check congressional and chart context in one workspace.

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Related reading

• Top whale tickers in August 2026
• Top whale tickers in July 2026
• How to triage whale transactions on ProBors
• Insider buying clusters: what to look for
• Why insider selling is usually not a signal

Sources

• SEC Form 4 overview — reporting requirements for insiders
• SEC EDGAR search — verify individual Form 4 filings
• SEC investor bulletin: Forms 3, 4, and 5
• Rows were checked in ProBors and should be verified against the original filing.
• Ingestion health: probors.com/status