Bond ETFs

MBB:what it yields, how rates move it and what it holds

iShares MBS ETF. Portfolio as of August 31, 2026, from the fund's SEC filing (Form N-PORT).

Mortgage-backed (MBS). Bonds repaid from home-loan payments, guaranteed by Fannie Mae, Freddie Mac or Ginnie Mae.

Yield to maturity (YTM)

not computed

98% of the fund is in mortgage-backed bonds. Their yield depends on when homeowners repay early, which public data does not show. Rather than a wrong number, we show none.

If rates rise 1 pointestimated from its duration, 5.7 years: -5.7%
Investment gradeof the credit risk, BBB or better: 100%
Size11,211 positions: $39.6B

In a few words

MBB holds 11,211 positions. 75% of the portfolio is bonds of Fannie Mae, Freddie Mac and similar agencies. We show no yield to maturity, because much of it is in bonds whose yield public data cannot give correctly. Its duration is 5.7 years: if rates rise by 1 percentage point, its price falls about 5.7%. In 2022, when rates rose sharply, its total return was -11.9%.

Every ETF in Mortgage-backed (MBS)

If rates change

A rough estimate, if rates moved at once and equally at every maturity.

5.7 years duration

Change in rates+1 point

Price, at once

-5.7%

Ready-made moves

Change in rates	At once
	+5.7%
	+2.8%
	0.0%
	-2.8%
	-5.7%
	-11.4%

Past returns

The ETF's total return, price change plus distributions, as the fund reports it to the SEC.

September 2019 – August 2026

Last 12 months

+3.0%

3 years, average per year

+4.6%

Worst 12 months

-15.0%

Largest fall from a peak

-16.8%

100 at the start 105.2 at the end, distributions reinvested

What it holds

Portfolio as of August 31, 2026: who issued the bonds, when they mature and the largest issuers.

11,211 positions4 issuers

Who issued the bonds

Fannie Mae, Freddie Mac and others74.8%

US federal agencies23.4%

Largest issuers

The 10 largest are 98.2% of the fund.

Fannie Mae43.20%

Freddie Mac28.39%

Government National Mortgage Association23.38%

UMBS, TBA3.25%

When they mature

Up to 1 year0.0%

1 to 3 years0.0%

3 to 5 years0.2%

5 to 10 years3.4%

10 to 20 years9.4%

Over 20 years85.2%

Details

Positions: 11,211
Average coupon: 3.72%
Floating rate: 0.0%
In other currencies: 0.0%
Mortgage-backed: 98.2%
In default: 0.00%
Hard to value: 0.00%
Cash and cash funds: 7.6%

Maturities as stated on the bonds. Mortgage bonds, many corporate bonds and city bonds can be repaid early, so in practice they mature sooner.

Similar bond ETFs

Same kind as MBB, nearest in rate sensitivity.

VMBSVanguard Mortgage-Backed Securities ETF
If rates +1%-5.4%

ETF	Yield (YTM)	If rates +1%	2022	Size
VMBSVanguard Mortgage-Backed Securities ETF	not computed	-5.4%	-11.6%	$17.6B

The full analysis

And what about stocks?

Bonds are only one side of investing. With Ploutos AI you can analyse a company through its official SEC filings, look into its financials and understand what lies behind the numbers. Every finding comes with a reference to its source, so you can check the data behind the analysis.

A fair value range built from the filings
Earnings quality, debt and red flags
Insider and institutional moves
The case for and the case against

Common questions

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How much would MBB fall if rates rose?

With a duration of 5.7 years, an immediate one-point rise in rates would take about 5.7% off its price. An equal fall would add about the same.

What is MBB's yield?

For this fund we show no yield to maturity, because much of it is in bonds whose yield public data cannot give correctly.

How did MBB do in 2022?

In 2022 MBB returned -11.9% in total, as the fund reports it.

US stocksThe market today, the sectors, the largest companies and the week's results.ETF overlapHow much of one ETF is already inside another, stock by stock, from the funds' SEC filings.US dividend stocksEach dividend's yield next to whether the company's cash covers it and whether it was ever cut.Methodology and sourcesWhere every figure comes from and how it is checked.

This page describes what bond ETFs hold, based on their SEC filings. Bond prices change every day and past returns do not say what comes next.