MASTERBRAND (MBC) Institutional Ownership & Top Holders
The most recent SEC Form 13F filings (Q1 2026) show 11 hedge funds and institutional investors holding a combined 33.5M shares of MASTERBRAND (MBC), valued at $278.3M. The median portfolio weight is 1.8%.
Quarterly institutional ownership changes in MBC show net buying, with the combined position increasing by 3.8M shares (12.9%) from the previous quarter.
Among 13F filers, the funds with the highest portfolio allocation to MBC are Coliseum (8.6% of its 13F portfolio), Pertento Partners (4.4%), and ACK Asset Management (3.8%). In Q1 2026, REDWOOD CAPITAL MANAGEMENT made the largest position increase (+1.6%), while Diameter Capital Partners made the largest reduction (-4.5%).
Top 10 Institutional Holders in MASTERBRAND (MBC), Ranked by Portfolio Weight
Based on the latest SEC Form 13F filings (Q1 2026).
| # | Fund | Shares | Market Value | Portfolio Weight |
|---|---|---|---|---|
| 1 | Coliseum | 12,694,710 | $105.5M | 8.6% |
| 2 | Pertento Partners | 4,964,821 | $41.3M | 4.4% |
| 3 | ACK Asset Management | 3,700,000 | $30.7M | 3.8% |
| 4 | Decagon Asset Management | 1,546,997 | $12.9M | 3.3% |
| 5 | Diameter Capital Partners | 1,545,571 | $12.8M | 2.5% |
| 6 | CANYON CAPITAL ADVISORS | 1,691,901 | $14.1M | 1.8% |
| 7 | REDWOOD CAPITAL MANAGEMENT | 1,286,097 | $10.7M | 1.6% |
| 8 | Melqart | 1,073,202 | $8.9M | 0.9% |
| 9 | Miller Value Partners | 104,854 | $871K | 0.2% |
| 10 | Glazer Capital | 1,065,129 | $8.9M | 0.2% |
- 11Institutional investors
- 33,487,296Shares held (disclosed)
- $278.3M13F market value
- 1.8%Median portfolio weight
Ownership History
Quarter-by-quarter share count, market value, and portfolio conviction weight (up to 5 of the heaviest weight-by-portfolio funds) of MBC. Sourced from 13F filings; reflects long equity positions only.
Quarter-over-Quarter ActivityQ1 2026
The biggest weight-increase and weight-decrease changes among funds that hold MBC. Deltas compare the selected filing to the previous reporting quarter.
Top buyers
- REDWOOD CAPITAL MANAGEMENT+1.6% · +1,286,097 shares
- Melqart+0.9% · +1,052,022 shares
- ACK Asset Management+0.7% · +1,400,000 shares
Top sellers
- Diameter Capital Partners-4.5% · -4,464,839 shares
- CANYON CAPITAL ADVISORS-1.0% · -268,865 shares
- Harris Associates-0.0% · -108,716 shares
Ownership Statistics
- Funds holding
- 11
- Median weight
- 1.8%
- Largest holder
- Coliseum · 8.6%
- Smallest holder
- Pzena Investment Management · 0.1%
- Shares held
- 33,487,296 (+3,814,093)
All Institutional HoldersSortable · searchable
All institutional investors (Max 50) holding MBC in the selected quarter. Click a fund name to drill into its full 13F portfolio.
| 1 | Coliseum | 12,694,710 | $105.5M | 8.6% |
| 2 | Pertento Partners | 4,964,821 | $41.3M | 4.4% |
| 3 | ACK Asset Management | 3,700,000 | $30.7M | 3.8% |
| 4 | Decagon Asset Management | 1,546,997 | $12.9M | 3.3% |
| 5 | Diameter Capital Partners | 1,545,571 | $12.8M | 2.5% |
| 6 | CANYON CAPITAL ADVISORS | 1,691,901 | $14.1M | 1.8% |
| 7 | REDWOOD CAPITAL MANAGEMENT | 1,286,097 | $10.7M | 1.6% |
| 8 | Melqart | 1,073,202 | $8.9M | 0.9% |
| 9 | Miller Value Partners | 104,854 | $871.3K | 0.2% |
| 10 | Glazer Capital | 1,065,129 | $8.9M | 0.2% |
| 11 | Pzena Investment Management | 3,814,014 | $31.7M | 0.1% |
Institutional Investor Count Over Time
Number of institutional investors disclosing a long position in MASTERBRAND INC (MBC) each reporting quarter. Sourced from SEC Form 13F-HR filings.
Methodology & FAQ
Methodology: How We Track MBC Institutional Holdings
Our data is systematically aggregated directly from quarterly Form 13F-HR disclosures submitted to the U.S. Securities and Exchange Commission (SEC).
- Who Must File (Reporting Threshold): This dataset includes filings from U.S. institutional investment managers, hedge funds, mutual funds, university endowments, and family offices managing at least $100 million in Section 13(f) securities (including equities, options, convertibles, ETFs, and warrants).
- What is Included (Data Scope): We capture long positions in Section 13(f) securities for MASTERBRAND INC (MBC). By SEC regulation, 13F filings do not require the disclosure of short positions, non-U.S. holdings, or OTC derivatives. Listed options are excluded from portfolio weight calculations to ensure comparability across filers.
- Portfolio Weight Explained (Metric Definition): “Portfolio Weight” shows how much of a fund's total reported 13F portfolio value (excluding listed options) is allocated to MBC on the specific reporting date.
- How to Use This Data (Interpretation): Quarter-over-quarter changes in shares and portfolio weight reflect a combination of active trading and market price movements. These are descriptive metrics of fund allocation, not explicit buy or sell signals.
How do you measure hedge fund conviction and institutional concentration in MBC?
We evaluate fund conviction by looking at portfolio weight rather than just absolute share count. By tracking how the largest holders —such as Coliseum , Pertento Partners , and ACK Asset Management as of Q1 2026— change their position sizing quarter-over-quarter, we help investors distinguish between deliberate position sizing changes and passive mark-to-market drift.
Does the MBC ownership data include short interest or options?
SEC Form 13F mandates the disclosure of long positions in Section 13(f) securities, which includes equities and listed options (put and call contracts), but excludes short interest, swaps, and OTC derivatives by regulatory design. On this platform, listed options are excluded from portfolio weight calculations to ensure comparability across filers.
Are family offices and university endowments included in this MBC data?
Yes. In addition to traditional hedge funds and large asset managers, any institutional entity exercising investment discretion over at least $100 million in Section 13(f) securities must file a Form 13F. This explicitly includes single-family offices and university endowments. If a qualifying family office or endowment holds MBC stock, their allocation is systematically aggregated alongside traditional fund data.
When is the institutional ownership data updated, and is there a reporting lag?
Institutional investment managers are required to file their Form 13F within 45 days after the end of a calendar quarter (the standard “T+45” window). Our platform re-ingests new filings from the SEC EDGAR database on a nightly cycle, typically within 24–48 hours of publication, providing a point-in-time snapshot of reported consensus positioning for MBC as of each filing date.