SEC Form 4
Black Stone Minerals, L.P. (BSM) insider trading
In the 12 months to Oct 26, 2026, 3 BSM insiders reported open-market sales of $29.5M across 5 filings; 2 insiders bought $2.4M.
Latest filing · Last 12 months · Source: SEC EDGAR · How we count
- Open-market sales
- $29.5M
- 5 filings · 3 insiders
- Open-market purchases
- $2.4M
- 4 filings
- Pre-arranged sales (10b5-1)
- 3 of 5
- $1.3M of $29.5M sold (4%)
Who traded BSM, and when
- Purchase
- Sale
- Sale, pre-arranged (10b5-1)
BSM daily close from Oct 27, 2025 to Oct 26, 2026, between $13.03 and $15.44, last $14.85. 5 sale and 4 purchase filings by 5 insiders, marked at their filing dates. James Whitehead, Director: sold $28.1M across 1 filing, first filed Aug 10, 2026, last Aug 10, 2026. D. Mark DeWalch, Director: bought $1.5M across 2 filings, first filed May 28, 2026, last Jun 2, 2026. Luke Stevens Putman, SVP, General Counsel, and Sec: sold $1.3M across 3 filings, first filed May 6, 2026, last May 6, 2026. Thomas L. Carter Jr., Executive Chairman: bought $924.5K across 2 filings, first filed May 12, 2026, last May 14, 2026. Ashley J. Longmaid, Director: sold $149.7K across 1 filing, first filed May 13, 2026, last May 13, 2026.
Largest mark · tap a row for others
James Whitehead · Director
Sale $28,099,057
2,127,105 shares at $13.21 avg
Filed Aug 10, 2026 · traded Aug 6
Close on filing date $14.38
James Whitehead · Director
Director
$28.1M soldD. Mark DeWalch · Director
Director
$1.5M boughtLuke Stevens Putman · SVP, General Counsel, and Sec
SVP, General Counsel, and Sec
$1.3M soldThomas L. Carter Jr. · Executive Chairman
Executive Chairman
$924.5K boughtAshley J. Longmaid · Director
Director
$149.7K soldOpen-market trades
9 filings in the last 12 months| Insider | Role | Sold | Bought | Filings | Pre-arranged (10b5-1) | Last filed |
|---|---|---|---|---|---|---|
| James Whitehead | Director | $28.1M | — | 1 | — | |
| D. Mark DeWalch | Director | — | $1.5M | 2 | — | |
| Luke Stevens Putman | SVP, General Counsel, and Sec | $1.3M | — | 3 | 100% of sales | |
| Thomas L. Carter Jr. | Executive Chairman | — | $924.5K | 2 | — | |
| Ashley J. Longmaid | Director | $149.7K | — | 1 | — |
| Filed | Insider | Type | Shares | Avg price | Value | Held after | Source |
|---|---|---|---|---|---|---|---|
traded | James Whitehead Director | Sale | 2,127,105 | $13.21 | $28.1M | Multiple accounts | |
traded | D. Mark DeWalch Director | Purchase | 72,726 | $13.55 | $985.4K | 631,248 | |
traded | D. Mark DeWalch Director | Purchase | 37,650 | $13.21 | $497.3K | 431,495 | |
traded | Thomas L. Carter Jr. Executive Chairman | Purchase | 1,120 | $13.50 | $15.1K | 3,682,724 | |
traded | Ashley J. Longmaid Director | Sale | 11,128 | $13.45 | $149.7K | 137,335 | |
traded | Thomas L. Carter Jr. Executive Chairman | Purchase | 67,758 | $13.42 | $909.3K | 3,681,604 | |
traded | Luke Stevens Putman SVP, General Counsel, and Sec | SalePre-arranged (10b5-1) | 30,276 | $15.25 | $461.6K | 761,417 | |
traded | Luke Stevens Putman SVP, General Counsel, and Sec | SalePre-arranged (10b5-1) | 29,386 | $13.75 | $404.0K | 702,645 | |
traded | Luke Stevens Putman SVP, General Counsel, and Sec | SalePre-arranged (10b5-1) | 29,386 | $14.45 | $424.7K | 732,031 |
GET /stocks/filings/vX/form-4?tickers=BSM&filing_date.gte=2025-10-26&sort=filing_date.desc&limit=500{
"status": "OK",
"results": [
{
"tickers": [
"BSM"
],
"issuer_cik": "0001621434",
"owner_cik": "0001987724",
"accession_number": "0001987724-26-000004",
"form_type": "4",
"filing_date": "2026-08-10",
"period_of_report": "2026-08-06",
"issuer_name": "Black Stone Minerals, L.P.",
"issuer_trading_symbol": "BSM",
"owner_name": "Whitehead James",
"is_director": true,
"is_officer": false,
"is_ten_percent_owner": false,
"is_other": false,
"security_type": "non_derivative",
"record_type": "transaction",
"security_title": "Common units representing limited partner interests",
"transaction_timeliness": "O",
"aff_10b5_one": false,
"transaction_date": "2026-08-06",
"transaction_code": "S",
"equity_swap_involved": false,
"transaction_shares": 1628762,
"transaction_price_per_share": 13.21,
"transaction_acquired_disposed": "D",
"shares_owned_following_transaction": 646058,
"transaction_value": 21515946.02,
"not_subject_to_section_16": false,
"direct_or_indirect": "I",
"nature_of_ownership": "By Lacy Properties Ltd.",
"footnotes": [
{
"id": "F1",
"description": "The Reporting Person has indicated that Eagle Gathering System Ltd., Lacy Properties Ltd., and R. Lacy Services Ltd. Retirement Plan plan to divest their common-unit positions by year-end 2026 for estate-planning and diversification purposes; the reported sales are part of that divestment plan."
}
]
},
{
"tickers": [
"BSM"
],
"issuer_cik": "0001621434",
"owner_cik": "0001987724",
"accession_number": "0001987724-26-000004",
"form_type": "4",
"filing_date": "2026-08-10",
"period_of_report": "2026-08-06",
"issuer_name": "Black Stone Minerals, L.P.",
"issuer_trading_symbol": "BSM",
"owner_name": "Whitehead James",
"is_director": true,
"is_officer": false,
"is_ten_percent_owner": false,
"is_other": false,
"security_type": "non_derivative",
"record_type": "transaction",
"security_title": "Common units representing limited partner interests",
"transaction_timeliness": "O",
"aff_10b5_one": false,
"transaction_date": "2026-08-06",
"transaction_code": "S",
"equity_swap_involved": false,
"transaction_shares": 498343,
"transaction_price_per_share": 13.21,
"transaction_acquired_disposed": "D",
"shares_owned_following_transaction": 0,
"transaction_value": 6583111.03,
"not_subject_to_section_16": false,
"direct_or_indirect": "I",
"nature_of_ownership": "By Eagle Gathering System Ltd.",
"footnotes": [
{
"id": "F1",
"description": "The Reporting Person has indicated that Eagle Gathering System Ltd., Lacy Properties Ltd., and R. Lacy Services Ltd. Retirement Plan plan to divest their common-unit positions by year-end 2026 for estate-planning and diversification purposes; the reported sales are part of that divestment plan."
}
]
}
]
}
// 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) · 52 records
- Tax withholding11 records
- Grants and awards39 records
- Gifts1 record
- Other1 record
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.
- Pre-arranged (10b5-1)
- The insider marked the filing as made under a trading plan set up in advance (SEC Rule 10b5-1). The mark covers the whole filing, and an unmarked filing may still be under a plan.
- Filing date
- Insiders have two business days to report a trade. Totals and the chart use the filing date, when the trade became public.
- Counted once
- When several owners (a fund and its partners, say) report the same trade, it's counted once. Corrected filings replace the originals.
Frequently asked questions
Has Black Stone Minerals, L.P.'s CEO sold stock?
No. Taylor DeWalch and Fowler Carter (CEOs) made no open-market sales filed as CEO in the last 12 months.
How current is BSM’s insider data?
These are BSM 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.
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Track BSM 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 BSM 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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