SPAB vs SPMB: Holdings Overlap
SPABState Street® SPDR® Portfolio Aggregate Bond ETF
State Street (SPDR) · 8489 holdings · $9.8B · as of 2026-08-06
SPMBState Street® SPDR® Portfolio Mortgage Backed Bond ETF
State Street (SPDR) · 2714 holdings · $7.0B · as of 2026-08-06
How similar are SPAB and SPMB?
State Street® SPDR® Portfolio Aggregate Bond ETF (SPAB, by State Street (SPDR)) holds 8489 positions; State Street® SPDR® Portfolio Mortgage Backed Bond ETF (SPMB, by State Street (SPDR)) holds 2714. They have 684 holdings in common, and by portfolio weight the two funds are 18.1% identical. In practical terms the pair is lightly overlapping, with most of each portfolio distinct.
- Overlap by Weight
- 18.1%Sum of the smaller weight of each shared holding
- Shared Holdings
- 684SPAB holds 8489 · SPMB holds 2714
- Weight in Shared Holdings
- SPAB 19%·SPMB 52%Share of each fund's weight in stocks both funds own
Based on each fund's latest official holdings. How is this calculated?
What makes each fund different
Only in SPAB
7805 of 8489 positions (79.9% of the fund) are not held by SPMB. Showing the top 30 by weight.
- US TREASURY N/B 12/28 3.50.77%
- US TREASURY N/B 11/28 4.3750.43%
- US TREASURY N/B 01/28 3.50.42%
- US TREASURY N/B 03/31 3.8750.41%
- US TREASURY N/B 11/34 4.250.38%
- US TREASURY N/B 12/27 3.3750.38%
Only in SPMB
2030 of 2714 positions (46.8% of the fund) are not held by SPAB. Showing the top 30 by weight.
- FNMA POOL MA4547 FN 02/52 FIXED 20.77%
- FNMA POOL FA0608 FN 02/55 FIXED VAR0.48%
- FED HM LN PC POOL RQ0137 FR 07/56 FIXED 5.50.42%
- GNMA II POOL MB0871 G2 01/56 FIXED 50.41%
- FNMA POOL CC0119 FN 03/55 FIXED 60.36%
- GNMA II POOL MB0365 G2 05/55 FIXED 50.35%
Performance
| Fund | 1M | YTD | 1Y | 3Y (ann.) | 5Y (ann.) | 10Y (ann.) | Yield |
|---|---|---|---|---|---|---|---|
| SPAB | -0.3% | +0.0% | +2.5% | +4.2% | -0.2% | +1.4% | 4.11% |
| SPMB | -0.1% | +0.5% | +3.9% | +4.7% | +0.2% | +1.2% | 4.15% |
Total returns including dividends, from adjusted daily closes as of 2026-08-07. 3Y/5Y/10Y are annualized. Yield is trailing-12-month distributions over the last close. Past performance does not predict future results.
Project the growth of $10,000 in SPAB vs SPMB →
Shared Holdings(684)
The top 10 shared positions account for 13% of the overlap, led by FNMA TBA 30 YR 5.5 SINGLE FAMILY MORTGAGE, FNMA TBA 30 YR 5 SINGLE FAMILY MORTGAGE and GNMA II TBA 30 YR 5 JUMBOS.
| FNMA TBA 30 YR 5.5 SINGLE FAMILY MORTGAGE | 0.38% | 0.91% | 0.38% |
|---|---|---|---|
| FNMA TBA 30 YR 5 SINGLE FAMILY MORTGAGE | 0.31% | 0.76% | 0.31% |
| GNMA II TBA 30 YR 5 JUMBOS | 0.24% | 0.53% | 0.24% |
| FNMA TBA 30 YR 6 SINGLE FAMILY MORTGAGE | 0.22% | 0.59% | 0.22% |
| FNMA TBA 30 YR 2.5 SINGLE FAMILY MORTGAGE | 0.22% | 0.30% | 0.22% |
| GNMA II TBA 30 YR 5.5 JUMBOS | 0.21% | 0.42% | 0.21% |
| FNMA POOL MA4465 FN 11/51 FIXED 2 | 0.20% | 0.46% | 0.20% |
| GNMA II POOL MB1216 G2 06/56 FIXED 5 | 0.20% | 0.41% | 0.20% |
| FED HM LN PC POOL RQ0094 FR 02/56 FIXED 5 | 0.19% | 1.15% | 0.19% |
| FED HM LN PC POOL RQ0040 FR 08/55 FIXED 5.5 | 0.19% | 0.35% | 0.19% |
| GNMA II TBA 30 YR 4.5 JUMBOS | 0.19% | 0.21% | 0.19% |
| FED HM LN PC POOL SD8106 FR 11/50 FIXED 2 | 0.19% | 0.32% | 0.19% |
| FED HM LN PC POOL RQ0041 FR 08/55 FIXED 6 | 0.16% | 0.74% | 0.16% |
| FED HM LN PC POOL SD8177 FR 11/51 FIXED 2 | 0.16% | 0.42% | 0.16% |
| FED HM LN PC POOL SD8128 FR 02/51 FIXED 2 | 0.15% | 0.28% | 0.15% |
| FNMA POOL MA4158 FN 10/50 FIXED 2 | 0.15% | 0.20% | 0.15% |
| FED HM LN PC POOL SD8299 FR 02/53 FIXED 5 | 0.15% | 0.26% | 0.15% |
| FED HM LN PC POOL SD8341 FR 07/53 FIXED 5 | 0.14% | 0.20% | 0.14% |
| FNMA POOL MA4437 FN 10/51 FIXED 2 | 0.14% | 0.36% | 0.14% |
| FED HM LN PC POOL SD8121 FR 01/51 FIXED 2 | 0.13% | 0.34% | 0.13% |
| FED HM LN PC POOL SD8166 FR 09/51 FIXED 2 | 0.13% | 0.29% | 0.13% |
| FED HM LN PC POOL RQ0056 FR 10/55 FIXED 5.5 | 0.13% | 0.40% | 0.13% |
| GNMA II TBA 30 YR 6 JUMBOS | 0.13% | 0.25% | 0.13% |
| FNMA TBA 30 YR 4.5 SINGLE FAMILY MORTGAGE | 0.13% | 0.33% | 0.13% |
| FED HM LN PC POOL SD8454 FR 08/54 FIXED 6 | 0.12% | 0.37% | 0.12% |
Showing the top 250 of 684 shared holdings by overlap weight.
Frequently Asked Questions
How much do SPAB and SPMB overlap?
SPAB and SPMB overlap by 18.1% of portfolio weight. They share 684 holdings (SPAB holds 8489 positions and SPMB holds 2714), based on each fund's latest SEC-reported holdings.
Is it redundant to own both SPAB and SPMB?
The two portfolios are 18.1% identical by weight. Owning both is not redundant. Most of each portfolio is distinct, so the funds can serve different roles.
What are the biggest shared holdings of SPAB and SPMB?
The largest positions held by both funds are FNMA TBA 30 YR 5.5 SINGLE FAMILY MORTGAGE, FNMA TBA 30 YR 5 SINGLE FAMILY MORTGAGE, GNMA II TBA 30 YR 5 JUMBOS, FNMA TBA 30 YR 6 SINGLE FAMILY MORTGAGE and FNMA TBA 30 YR 2.5 SINGLE FAMILY MORTGAGE. Together the top 10 shared positions account for 13% of the total overlap.
What does SPAB own that SPMB doesn't?
7805 positions (79.9% of SPAB) are unique to SPAB, led by US TREASURY N/B 12/28 3.5, US TREASURY N/B 11/28 4.375 and US TREASURY N/B 01/28 3.5. In the other direction, 2030 positions (46.8% of SPMB) are unique to SPMB.