iShares MBS ETF
MBB
936 hedge funds and large institutions have $34.5B invested in iShares MBS ETF in 2025 Q2 according to their latest regulatory filings, with 98 funds opening new positions, 410 increasing their positions, 312 reducing their positions, and 84 closing their positions.
461% more call options, than puts
Call options by funds: $9.16M | Put options by funds: $1.63M
31% more repeat investments, than reductions
Existing positions increased: 410 | Existing positions reduced: 312
17% more first-time investments, than exits
New positions opened: 98 | Existing positions closed: 84
8% more capital invested
Capital invested by funds: $32B → $34.5B (+$2.49B)
0.82% more ownership
Funds ownership: 86.69% → 87.51% (+0.82%)
1% more funds holding
Funds holding: 931 → 936 (+5)
13% less funds holding in top 10
Funds holding in top 10: 68 → 59 (-9)
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
TIAA Trust, National Association
Charlotte,
North Carolina
|
+$1.73B |
| 2 |
Barclays
London,
United Kingdom
|
+$399M |
| 3 |
Bank of America
Charlotte,
North Carolina
|
+$166M |
| 4 |
Prudential Financial
Newark,
New Jersey
|
+$134M |
| 5 |
Royal Bank of Canada
Toronto,
Ontario, Canada
|
+$105M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
State of Tennessee, Department of Treasury
Nashville,
Tennessee
|
-$233M |
| 2 |
RWP
RWA Wealth Partners
Newton,
Massachusetts
|
-$111M |
| 3 |
Jane Street
New York
|
-$89.1M |
| 4 |
UBS Group
Zurich,
Switzerland
|
-$65.9M |
| 5 |
HCM
Hilton Capital Management
Garden City,
New York
|
-$48.8M |
MBB Hedge Fund Activity: Q2 2025 in Review
936 of the 7,595 institutional investors tracked by Wall St. Rank reported a position in iShares MBS ETF (MBB) for Q2 2025, worth a combined $34.5B — up 7.8% from $32B a quarter earlier.
Buyers outnumbered sellers: 98 funds opened new MBB positions and 84 closed out — a net gain of 14 holders — while 410 added to existing stakes and 312 trimmed.
The largest buyer was TIAA Trust, National Association, adding an estimated $1.73B. The largest seller was State of Tennessee, Department of Treasury, cutting an estimated $233M.
- 936 institutional investors held iShares MBS ETF (MBB) as of Q2 2025, up from 931 in Q1 2025.
- Funds reported $34.5B of iShares MBS ETF stock for Q2 2025, up 7.8% quarter-over-quarter.
- 98 funds opened new iShares MBS ETF positions in Q2 2025 and 84 closed out, a net change of +14 holders.
- The largest iShares MBS ETF buyer in Q2 2025 was TIAA Trust, National Association, an estimated $1.73B added.
- The largest iShares MBS ETF seller in Q2 2025 was State of Tennessee, Department of Treasury, an estimated $233M sold.
Based on aggregated 13F filings for Q2 2025.