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ETF comparison

SPMB vs VMBS

Both US Aggregate Bond.

State Street SPDR Portfolio Mortgage Backed Bond ETF · Vanguard Mortgage-Backed Securities Index Fund ETF Shares

Holdings overlap

Weighted by ISIN/CUSIP
19.8 %

782 positions appear in both funds. Buying equal dollars of SPMB and VMBS would leave roughly 19.8% of each dollar exposed to the same underlying securities.

SPMB only 78.4% Shared 19.8% VMBS only 78.9%
In SPMB only
1,871 positions
Shared
782 positions
In VMBS only
4,230 positions

Side by side

SPMB

State Street SPDR Portfolio Mortgage Backed Bond ETF

State Street · US Aggregate Bond

86 composite / 100
Expense ratio
0.040%
Net assets
$7.07B
TTM yield
4.11%
Top-10 conc.
13.6%
VMBS

Vanguard Mortgage-Backed Securities Index Fund ETF Shares

Vanguard · US Aggregate Bond

89 composite / 100
Expense ratio
0.030%
Net assets
$17.34B
TTM yield
4.20%
Top-10 conc.
7.5%

Sub-score comparison

96
Cost
97
52
Tax efficiency
52
93
Liquidity
100
95
Concentration
100
—
Tracking quality
—
SPMB sub-score VMBS

Tracking quality isn't part of the composite — see what we don't score for why.

Cost difference

VMBS is 1 bps cheaper than SPMB. On a $100,000 position that's about $10/yr more in fees for SPMB.

Fee figure is the annual expense charged on $100,000. To see how the gap compounds over a multi-decade holding period, open the cost calculator pre-filled with SPMB vs VMBS.

Top shared holdings

782 shared in total
# Holding In SPMB In VMBS Overlap
1 Freddie Mac 0.30% 0.25% 0.25%
2 Freddie Mac 0.22% 0.22% 0.22%
3 Government National Mortgage Association 0.30% 0.21% 0.21%
4 Government National Mortgage Association 0.32% 0.21% 0.21%
5 Freddie Mac 0.36% 0.21% 0.21%
6 Fannie Mae 0.31% 0.19% 0.19%
7 Fannie Mae 0.27% 0.19% 0.19%
8 Government National Mortgage Association 0.38% 0.19% 0.19%
9 Freddie Mac 0.46% 0.19% 0.19%
10 Government National Mortgage Association 0.19% 0.19% 0.19%
11 Fannie Mae 0.27% 0.18% 0.18%
12 Government National Mortgage Association 0.37% 0.17% 0.17%

Only in SPMB

1,871 total
  • Fannie Mae 0.83%
  • Freddie Mac 0.64%
  • UMBS, TBA 0.60%
  • Government National Mortgage Association 0.52%
  • Fannie Mae 0.50%
  • Freddie Mac 0.48%
  • UMBS, TBA 0.48%
  • Fannie Mae 0.47%
  • Freddie Mac 0.46%
  • Government National Mortgage Association 0.45%

Only in VMBS

4,230 total
  • Ginnie Mae II Pool 0.44%
  • Fannie Mae or Freddie Mac 0.43%
  • Fannie Mae or Freddie Mac 0.34%
  • Fannie Mae or Freddie Mac 0.32%
  • Ginnie Mae II Pool 0.29%
  • Freddie Mac Pool 0.29%
  • Ginnie Mae II Pool 0.28%
  • Freddie Mac Pool 0.27%
  • Fannie Mae or Freddie Mac 0.26%
  • Ginnie Mae II Pool 0.22%

Open SPMB or VMBS at a brokerage

Both funds trade commission-free at major US brokerages.

Open at Fidelity

Affiliate links — opening an account through these earns PlainIndex a one-time referral. Scoring is computed before any affiliate consideration; see our methodology and funding disclosure.

Holdings overlap is the sum of min(weight_a, weight_b) over positions matched on ISIN (CUSIP fallback). Methodology: see /methodology/.

Comparing two funds doesn't endorse swapping one for the other. Tax-lot history, account type, and personal goals matter — PlainIndex publishes data and methodology, not investment advice.