SEC Form 4
Compass Therapeutics, Inc. (CMPX) insider trading
In the 12 months to Oct 26, 2026, 2 CMPX insiders reported open-market purchases of $96.9K across 4 filings; no open-market sales were filed.
Latest filing · Last 12 months · Source: SEC EDGAR · How we count
- Open-market sales
- $0
- 0 filings · 0 insiders
- Open-market purchases
- $96.9K
- 4 filings
Who traded CMPX, and when
- Purchase
CMPX daily close from Oct 27, 2025 to Oct 26, 2026, between $0.75 and $6.69, last $0.75. 0 sale and 4 purchase filings by 2 insiders, marked at their filing dates. Neil Lerner, Chief Accounting Officer: bought $49.6K across 3 filings, first filed Apr 30, 2026, last Oct 2, 2026. Jonathan Anderman, General Counsel: bought $47.3K across 1 filing, first filed Apr 30, 2026, last Apr 30, 2026.
Largest mark · tap a row for others
Jonathan Anderman · General Counsel
Purchase $47,250
25,000 shares at $1.89 avg
Filed Apr 30, 2026 · traded Apr 29
Close on filing date $1.77
Neil Lerner · Chief Accounting Officer
Chief Accounting Officer
$49.6K boughtJonathan Anderman · General Counsel
General Counsel
$47.3K boughtOpen-market trades
4 filings in the last 12 months| Insider | Role | Sold | Bought | Filings | Pre-arranged (10b5-1) | Last filed |
|---|---|---|---|---|---|---|
| Neil Lerner | Chief Accounting Officer | — | $49.6K | 3 | — | |
| Jonathan Anderman | General Counsel | — | $47.3K | 1 | — |
| Filed | Insider | Type | Shares | Avg price | Value | Held after | Source |
|---|---|---|---|---|---|---|---|
traded | Neil Lerner Chief Accounting Officer | Purchase | 20,000 | $0.92 | $18.4K | 420,000 | |
traded | Neil Lerner Chief Accounting Officer | Purchase | 2,500 | $1.14 | $2.8K | 400,000 | |
traded | Jonathan Anderman General Counsel | Purchase | 25,000 | $1.89 | $47.3K | 196,000 | |
traded | Neil Lerner Chief Accounting Officer | Purchase | 15,000 | $1.89 | $28.4K | 397,500 |
GET /stocks/filings/vX/form-4?tickers=CMPX&filing_date.gte=2025-10-26&sort=filing_date.desc&limit=500{
"status": "OK",
"results": [
{
"tickers": [
"CMPX"
],
"issuer_cik": "0001738021",
"owner_cik": "0001505148",
"accession_number": "0001171843-26-006349",
"form_type": "4",
"filing_date": "2026-10-02",
"period_of_report": "2026-10-01",
"issuer_name": "Compass Therapeutics, Inc.",
"issuer_trading_symbol": "CMPX",
"owner_name": "Lerner Neil",
"is_director": false,
"is_officer": true,
"is_ten_percent_owner": false,
"is_other": false,
"officer_title": "Chief Accounting Officer",
"security_type": "non_derivative",
"record_type": "transaction",
"security_title": "Common Stock",
"transaction_timeliness": "O",
"aff_10b5_one": false,
"transaction_date": "2026-10-01",
"transaction_code": "P",
"equity_swap_involved": false,
"transaction_shares": 20000,
"transaction_price_per_share": 0.92,
"transaction_acquired_disposed": "A",
"shares_owned_following_transaction": 420000,
"transaction_value": 18400,
"not_subject_to_section_16": false,
"direct_or_indirect": "D",
"footnotes": [
{
"id": "F1",
"description": "62,500 of the shares represents unvested restricted stock units (\"RSU\") granted on January 2, 2026. Each RSU represents a contingent right to receive one share of common stock. The award is subject to service-based vesting conditions and vests in four equal annual installments, with the first installment vested on January 2, 2027."
}
]
},
{
"tickers": [
"CMPX"
],
"issuer_cik": "0001738021",
"owner_cik": "0001505148",
"accession_number": "0001171843-26-006235",
"form_type": "4",
"filing_date": "2026-09-25",
"period_of_report": "2026-09-24",
"issuer_name": "Compass Therapeutics, Inc.",
"issuer_trading_symbol": "CMPX",
"owner_name": "Lerner Neil",
"is_director": false,
"is_officer": true,
"is_ten_percent_owner": false,
"is_other": false,
"officer_title": "Chief Accounting Officer",
"security_type": "non_derivative",
"record_type": "transaction",
"security_title": "Common Stock",
"transaction_timeliness": "O",
"aff_10b5_one": false,
"transaction_date": "2026-09-24",
"transaction_code": "P",
"equity_swap_involved": false,
"transaction_shares": 2500,
"transaction_price_per_share": 1.14,
"transaction_acquired_disposed": "A",
"shares_owned_following_transaction": 400000,
"transaction_value": 2849.9999999999995,
"not_subject_to_section_16": false,
"direct_or_indirect": "D",
"footnotes": [
{
"id": "F1",
"description": "62,500 of the shares represents unvested restricted stock units (\"RSU\") granted on January 2, 2026. Each RSU represents a contingent right to receive one share of common stock. The award is subject to service-based vesting conditions and vests in four equal annual installments, with the first installment vested on January 2, 2027."
}
]
}
]
}
// trimmed to 2 resultsThe response includes every Form 4 record; this page keeps open-market purchases and sales on common stock and removes duplicate joint-filer rows.
Other insider activity (not market trades) · 9 records
- Tax withholding3 records
- Grants and awards6 records
Reported on Form 4 but not purchases or sales in the market, so not counted in the totals above.
How to read this page
- Open-market purchase or sale
- A buy or sell of the company's stock at market price. Grants, option exercises, shares withheld for tax, gifts and employee stock plan purchases are listed separately and not counted.
- Filing date
- Insiders have two business days to report a trade. Totals and the chart use the filing date, when the trade became public.
Frequently asked questions
Has Compass Therapeutics, Inc.'s CEO sold stock?
No. Thomas J. Schuetz (CEO) made no open-market sales filed as CEO in the last 12 months.
How current is CMPX’s insider data?
These are CMPX Form 4 filings from the last year, refreshed daily. The Massive Form 4 API has the full, continuously updated record.
What counts as an open-market buy or sell?
Only purchases and sales at the market price. Option exercises, grants, gifts, and shares withheld for taxes are reported on Form 4 but are left out of the buy and sell totals.
Build with AI
Track CMPX insider trades with your agent
This page joins two Massive endpoints: Form 4 filings and daily prices. Ask an agent to watch for new filings:
Using the Massive API (massive.com/docs/llms.txt), check Form 4 filings for CMPX every day with transaction_code=P and tell me when an insider files an open-market purchase, with their role, shares, price and the filing link.
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