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ETF comparison

MBB vs SHY

US Aggregate Bond vs US Treasury (Short).

iShares MBS ETF · iShares 1-3 Year Treasury Bond ETF

Holdings overlap

Weighted by ISIN/CUSIP
0.0 %

0 positions appear in both funds. Buying equal dollars of MBB and SHY would leave roughly 0.0% of each dollar exposed to the same underlying securities.

MBB unmatched 98.2% Shared 0.0% SHY unmatched 99.0%

Unmatched is the part of a fund's weight the other fund doesn't match: names only it holds, plus any extra weight it puts in names both funds hold.

In MBB only
11,209 positions
Shared
0 positions
In SHY only
90 positions

Side by side

MBB

iShares MBS ETF

iShares · US Aggregate Bond

89 composite / 100
Expense ratio
0.040%
Net assets
$35.89B
TTM yield
4.09%
Top-10 conc.
6.6%
SHY

iShares 1-3 Year Treasury Bond ETF

iShares · US Treasury (Short)

83 composite / 100
Expense ratio
0.15%
Net assets
$27.44B
TTM yield
3.30%
Top-10 conc.
15.4%

Sub-score comparison

96
Cost
85
52
Tax efficiency
59
100
Liquidity
100
100
Concentration
N/A
—
Tracking quality
—
MBB sub-score SHY

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

Cost difference

MBB is 11 bps cheaper than SHY. On a $100,000 position that's about $110/yr more in fees for SHY.

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 MBB vs SHY.

Top shared holdings

0 shared in total

No shared holdings between these funds.

Only in MBB

11,209 total
  • Government National Mortgage Association 1.05%
  • Freddie Mac 0.98%
  • UMBS, TBA 0.85%
  • UMBS, TBA 0.70%
  • Government National Mortgage Association 0.53%
  • Government National Mortgage Association 0.51%
  • Government National Mortgage Association 0.51%
  • Government National Mortgage Association 0.50%
  • Government National Mortgage Association 0.49%
  • Fannie Mae 0.49%

Only in SHY

90 total
  • United States of America 1.97%
  • United States of America 1.71%
  • United States of America 1.61%
  • United States of America 1.51%
  • United States of America 1.49%
  • United States of America 1.48%
  • United States of America 1.47%
  • United States of America 1.40%
  • United States of America 1.39%
  • United States of America 1.39%

Percentages are holdings overlap with the named fund.

Open MBB or SHY 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 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.