Security Snapshot

OCTAVE SPECIALTY GROUP INC - Common Stock (OSG) Institutional Ownership

CUSIP: 023139884

13F Institutional Holders and Ownership History from Q1 2014 to Q3 2026

13F reference period

Q2 2026

Institutions Reporting

147

Shares (Excl. Options)

30.07MFull value: 30,067,995 · shares · 30 Jun 2026

Price

$6.24

The headline uses the Q2 2026 reference period after its reporting deadline. Available reports may still be incomplete or amended. Newer periods in the history table contain incoming reports and may be incomplete.

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Latest holder snapshot 5 signals
Portfolio coverage rank
0%
Share change
-2,160,679
Value change
-$12,044,401
Number of holders
147
Issuer context Names, identifiers, and filing context for this profile. 3 identity fields
Shares outstanding
45,039,266
SEC-reported price per share
$4.14
Insider filing price
$4.14
13F Shares, Excluding Options vs Price
13F Value, Excluding Options
Total Investors
Filing notes and source

Key facts

  • OSG - OCTAVE SPECIALTY GROUP INC - Common Stock is tracked under CUSIP 023139884.
  • 147 institutions reported positions in Q2 2026.
  • 6 significant owners is listed from Schedule 13D/13G reporting.

Change

  • Holder count moved from 146 to 147 between Q1 2026 and Q2 2026.
  • SEC-reported value moved from
    $151.12MFull value: $151,121,884 · USD · 31 Mar 2026
    to
    $187.56MFull value: $187,560,502 · USD · 30 Jun 2026
    .

Research use

  • You can quickly see who holds this security, then open quarter and manager detail pages for full evidence.
  • 13F and Schedule 13D/13G sections are kept together so you can cross-check institutional and beneficial ownership context.

Evidence

Source: SEC Form 13F

Latest holder context comes from 147 institutions filings for Q2 2026.

Open SEC evidence

Security key

023139884

13F reference period

Q2 2026

13F holders

147

13D/G owners

6

CIK / CUSIP context first

13D/G owners

Significant owners

Large-stake holder rows connected to Schedule 13D/G evidence.

Rows
6
Security
OSG
Filer Ownership Change % Holdings Value Net Change Nb Shares Change % Reporting Name Report Period
BlackRock, Inc. 7.6% -12% $29,497,691 -$3,891,879 3,535,664 -12% BlackRock, Inc. 30 Sep 2025
VANGUARD CAPITAL MANAGEMENT LLC 5% $14,414,367 2,269,979 Vanguard Capital Management 30 Jun 2026
Western Standard LLC 5% -15% $10,451,298 -$1,510,576 2,247,591 -13% Western Standard LLC 31 Mar 2026
DIMENSIONAL FUND ADVISORS LP 4.6% $17,855,690 2,141,047 Dimensional Fund Advisors LP 30 Sep 2025
SUSQUEHANNA SECURITIES, LLC 2.2% -58% $8,484,349 -$11,354,702 1,017,308 -57% G1 Execution Services, LLC 30 Sep 2025
JANE STREET GROUP, LLC 1.7% -74% $3,586,936 -$7,469,620 771,384 -68% JANE STREET GROUP, LLC 31 Mar 2026
As of 30 Jun 2026, 147 institutional investors reported holding
30.07MFull value: 30,067,995 · shares · 30 Jun 2026
shares of OCTAVE SPECIALTY GROUP INC - Common Stock (OSG). This represents 67% of the company’s total
45.04MFull value: 45,039,266 · shares · Stored outstanding share count
outstanding shares.

13F concentration

Top 25 institutional shareholders

Largest 13F positions for this security by reported shares and value.

Top holder share
52%
Institution Ownership % Shares Held Share Change % Portfolio % Holdings Value
BlackRock, Inc. 10% 4,572,516 +17% 0% $28,532,501
Western Standard LLC 5% 2,247,591 0% 4.8% $14,024,968
VANGUARD CAPITAL MANAGEMENT LLC 4.4% 1,972,619 +1.4% 0% $12,309,143
Prescott Group Capital Management, L.L.C. 3.7% 1,647,793 +3.5% 0.89% $10,282,228
THIRD AVENUE MANAGEMENT LLC 3% 1,341,879 +0.05% 1.3% $8,373,325
Bain Capital Credit, LP 2.5% 1,108,012 0% 1.9% $6,913,995
GEODE CAPITAL MANAGEMENT, LLC 2.5% 1,106,335 +8.2% 0% $6,905,205
STATE STREET CORP 2% 898,673 -4.5% 0% $5,607,720
DIMENSIONAL FUND ADVISORS LP 1.6% 716,947 -45% 0% $4,474,177
JACOBS LEVY EQUITY MANAGEMENT, INC 1.4% 649,530 -27% 0.01% $4,053,067
MARSHALL WACE, LLP 1.3% 601,796 -44% 0% $3,755,206
ZACKS INVESTMENT MANAGEMENT 1.3% 590,370 0.03% $3,683,920
Bracebridge Capital, LLC 1.3% 579,234 0% 0.78% $3,614,420
MORGAN STANLEY 1.3% 569,563 +142% 0% $3,554,074
GOLDMAN SACHS GROUP INC 1.2% 560,756 +62% 0% $3,499,118
RIHO Partners, LLC 1.2% 554,818 +1.5% 1.9% $3,462,064
ESSEX INVESTMENT MANAGEMENT CO LLC 1.2% 539,289 +29% 0.44% $3,365,163
GENDELL JEFFREY L 1.1% 494,092 -65% 0.03% $3,083,134
Wolf Hill Capital Management, LP 1.1% 480,187 -67% 0.29% $2,996,367
Nuveen, LLC 0.95% 428,165 -46% 0% $2,671,751
CITADEL ADVISORS LLC 0.94% 422,777 -2.1% 0% $2,638,128
Caption Management, LLC 0.93% 419,136 -35% 0.09% $2,615,409
VANGUARD PORTFOLIO MANAGEMENT LLC 0.87% 392,350 +33% 0% $2,448,264
CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.84% 377,869 +28% 0% $2,357,903
NORTHERN TRUST CORP 0.78% 352,680 +9.4% 0% $2,200,723

Quarter history

Institutional holders across reporting periods

Holder count, reported shares/value, and median price by quarter.

Periods
51
Headline period
Q2 2026
Rows shown
1-25 of 51
Period 13F Shares, Excl. Options Value, Excl. Options Value Change Price (Median) Investors
2026 Q3 42,801 $186,407 -$3,610,990 $4.14 15
2026 Q2 30,067,995 $187,560,502 -$12,044,401 $6.24 147
2026 Q1 32,501,333 $151,121,884 -$13,743,220 $4.65 146
2025 Q4 34,704,270 $270,000,146 -$15,016,916 $7.78 144
2025 Q3 36,420,483 $303,620,140 +$5,517,493 $8.34 126
2025 Q2 36,967,187 $262,451,287 -$6,275,007 $7.10 145
2025 Q1 37,285,182 $325,247,075 -$39,529,091 $8.75 170
2024 Q4 41,463,461 $522,340,751 +$15,664,277 $12.65 179
2024 Q3 40,273,968 $449,624,914 +$10,695,609 $11.21 179
2024 Q2 38,733,238 $496,535,322 +$10,201,544 $12.82 182
2024 Q1 37,851,350 $591,468,537 -$4,976,804 $15.63 172
2023 Q4 38,145,550 $628,407,255 +$31,651,145 $16.48 174
2023 Q3 36,343,104 $438,745,752 -$11,313,309 $12.06 166
2023 Q2 37,227,104 $529,566,033 -$22,316,812 $14.24 159
2023 Q1 38,580,360 $596,164,176 +$63,723,924 $15.48 156
2022 Q4 34,499,926 $600,947,413 +$62,491,641 $17.44 165
2022 Q3 31,445,947 $401,072,377 -$34,274,712 $12.75 148
2022 Q2 36,839,151 $417,676,977 -$31,197,327 $11.35 137
2022 Q1 37,774,546 $392,130,695 -$17,253,058 $10.40 140
2021 Q4 37,338,742 $598,873,108 +$13,548,357 $16.05 129
2021 Q3 36,051,024 $516,212,696 -$1,311,166 $14.32 126
2021 Q2 36,096,104 $565,003,596 -$9,221,478 $15.66 122
2021 Q1 36,524,284 $611,655,331 -$28,313,721 $16.74 135
2020 Q4 37,401,411 $575,050,561 -$4,694,044 $15.38 134
2020 Q3 36,718,299 $468,543,199 -$11,638,357 $12.77 127
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