ETF comparison

MBBvsVMBS

Both US Aggregate Bond.

iShares MBS ETF · Vanguard Mortgage-Backed Securities Index Fund ETF Shares

Holdings overlap

Weighted by ISIN/CUSIP
17.2%

1,212 positions appear in both funds. Buying equal dollars of MBB and VMBS would leave roughly17.2%of each dollar exposed to the same underlying securities.

MBB only 87.7%Shared 17.2%VMBS only 82.1%
In MBB only
9,933 positions
Shared
1,212 positions
In VMBS only
3,900 positions

Side by side

MBB

iShares MBS ETF

iShares · US Aggregate Bond

88composite / 100
Expense ratio
0.040%
Net assets
$39.63B
TTM yield
4.42%
Top-10 conc.
13.1%
VMBS

Vanguard Mortgage-Backed Securities Index Fund ETF Shares

Vanguard · US Aggregate Bond

89composite / 100
Expense ratio
0.030%
Net assets
$17.59B
TTM yield
4.32%
Top-10 conc.
8.0%

Sub-score comparison

96
Cost
97
52
Tax efficiency
52
100
Liquidity
100
96
Concentration
100
Tracking quality
MBBsub-scoreVMBS

Tracking quality isn't part of the composite — seewhat we don't scorefor why.

Cost difference

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

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

Top shared holdings

1,212 shared in total
#HoldingIn MBBIn VMBSOverlap
1Government National Mortgage Association0.55%0.32%0.32%
2Government National Mortgage Association0.95%0.29%0.29%
3Freddie Mac1.05%0.26%0.26%
4Freddie Mac0.22%0.20%0.20%
5UMBS, TBA0.34%0.20%0.20%
6Government National Mortgage Association0.31%0.20%0.20%
7Fannie Mae0.30%0.18%0.18%
8Freddie Mac0.24%0.16%0.16%
9Government National Mortgage Association0.20%0.16%0.16%
10Government National Mortgage Association0.67%0.15%0.15%
11UMBS, TBA0.83%0.15%0.15%
12Fannie Mae0.15%0.18%0.15%

Only in MBB

9,933 total
  • BLACKROCK CASH FUNDS6.77%
  • Government National Mortgage Association0.53%
  • Fannie Mae0.52%
  • Government National Mortgage Association0.46%
  • Fannie Mae0.44%
  • Fannie Mae0.44%
  • Fannie Mae0.33%
  • Fannie Mae0.33%
  • Government National Mortgage Association0.28%
  • Fannie Mae0.28%

Only in VMBS

3,900 total
  • Ginnie Mae II Pool0.36%
  • Fannie Mae Pool0.29%
  • Freddie Mac Pool0.27%
  • Freddie Mac Pool0.27%
  • Fannie Mae or Freddie Mac0.25%
  • Freddie Mac Pool0.24%
  • Freddie Mac Pool0.24%
  • Ginnie Mae II Pool0.20%
  • Fannie Mae Pool0.20%
  • Ginnie Mae II Pool0.19%

Open MBB or VMBS at a brokerage

Both funds trade commission-free at major US brokerages.

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