Octave Specialty Group, Inc. (OSG)
NYSE: OSG · Surety Insurance · New York, NY · filing with the SEC since 1994
Who owns Octave Specialty Group, Inc.
As filed with the SECHolders of 5% or more
3
Blackrock, Inc. holds 7.6% of Common Stock, as its SCHEDULE 13G/A filed Oct 17, 2025 says.
Directors and officers
13
report now, of 20 people on the record since 2009. Their holdings as a group are not read here.
Institutions as a whole
n/a
The record does not read the share held by managers that file Form 13F, so none is printed and no split of the rest is estimated. What it holds is the 3 named at left.
Holders of 5% or moreshare of the class, as filed
Blackrock, Inc.
SCHEDULE 13G/A · filed Oct 17, 2025 · Common Stock · 8.7% in Apr 3, 2025
BlackRock Portfolio Management LLC
SCHEDULE 13G · filed Oct 27, 2026 · Common Stock
Vanguard Capital Management
SCHEDULE 13G · filed Jul 31, 2026 · Common Stock
Western Standard LLC
SCHEDULE 13G/A · filed May 11, 2026 · Common Stock, $0.01 par value per share · reported falling below 5%, from 5.87% in Feb 12, 2026
Dimensional Fund Advisors LP
SCHEDULE 13G/A · filed Oct 9, 2025 · Common Stock · reported falling below 5%
G1 Execution Services, LLC
SCHEDULE 13G/A · filed Nov 13, 2025 · Common Stock, $0.01 par value per share · reported falling below 5%, from 5.1% in Aug 14, 2025
Jane Street Group, LLC
SCHEDULE 13G/A · filed May 11, 2026 · Common stock par value $0.01 per share · reported falling below 5%, from 5.4% in Feb 11, 2026
The Vanguard Group
SCHEDULE 13G/A · filed Mar 27, 2026 · Common Stock · reported falling below 5%, from 5.75% in Apr 30, 2025
What OSG reports owning in othersstakes of 5% or more, and other ties
Other ties the annual report names
Ambac Uk
An entity · legal entity · owns, named in the 10-K filed Mar 4, 2026
Armaca Corp
An entity · legal entity · owns, named in the 10-K filed Mar 4, 2026
29 subsidiaries in 2 countries, from the list filed with the 10-K filed Mar 4, 2026.
Insider tradesForm 4
0sales
2purchases
0sales on a scheduled plan
0people selling
$0sold, in dollars
$100,000bought, in dollars
Open-market trades on Form 4 from Oct 6, 2025 to Oct 6, 2026. A scheduled plan is a selling program set in advance under SEC rule 10b5-1. The trades are listed as filed and do not feed the grade.
By calendar yearSoldBought
2026 runs to Oct 6, 2026. Dollars as filed, summed by the transaction date.
People who traded in the window2 of 20 on the roster
| Person | Role as filed | Sales | Sold | On a plan | Buys | Bought |
|---|---|---|---|---|---|---|
| Leblanc Claude | Chief Executive Officer | 0 | $0 | 0 | 1 | $100,000 |
| Smith R Sharon | Exec VP & Group COO | 0 | $0 | 0 | 1 | $0 |