MBB is the iShares MBS ETF, a Other ETF.

What is the expense ratio of MBB?

Expense ratio data for MBB is shown on the page when available from our data provider.

What are the largest holdings in MBB?

Top holdings include BLACKROCK CASH CL INST SL AGENCY, USD CASH, GNMA2 30YR TBA(REG C) 5.50% 09/21/2026, FHLMC 30YR UMBS SUPER 2.00% 05/01/2051, UMBS 30YR TBA(REG A) 5.50% 09/14/2026.

How can PortView analyze MBB overlap with other ETFs?

PortView computes the holdings overlap between MBB and the other ETFs and stocks you own, plus your combined sector and geographic exposure, so you can see true diversification.

iShares MBS (MBB) ETF Holdings & Analysis

ETFOther

$92.31-0.11%

1-year price historyRange $92.32 – $96.91

52-week range$92.31

$92.28$96.97

What MBB does

The iShares MBS ETF, known by its symbol MBB, is structured to mirror the financial performance of a specific index. This index is made up of premium, mortgage-backed pass-through securities that have been either provided or secured by agencies of the United States government.

Fund profile

Top holdings

	Holding	Weight
	BLACKROCK CASH CL INST SL AGENCY	6.76%
	USD CASH	5.46%
	GNMA2 30YR TBA(REG C) 5.50% 09/21/2026	0.94%
	FHLMC 30YR UMBS SUPER 2.00% 05/01/2051	0.87%
	UMBS 30YR TBA(REG A) 5.50% 09/14/2026	0.76%
	UMBS 30YR TBA(REG A) 5.00% 09/14/2026	0.63%
	GNMA2 30YR TBA(REG C) 5.00% 09/21/2026	0.47%
	GNMA2 30YR 5.00% 11/20/2054	0.46%
	GNMA2 30YR 2.00% 10/20/2051	0.45%
	GNMA2 30YR 2.00% 12/20/2051	0.44%

Sector allocation

Cash & Others

100.00%

Geographic allocation

Other

100.00%

PortView Portfolio Insights

PortView analyzes how MBB fits your actual portfolio — position weight, ETF overlap with your other funds, sector and geographic exposure, concentration, and how this fund contributes to your portfolio risk and return. Connect a portfolio to see your personalized figures; PortView never shows another user's private holdings.

Analyze MBB in PortView →

Related securities

Frequently asked questions

What does MBB track?: MBB is the iShares MBS ETF, a Other ETF.
What is the expense ratio of MBB?: Expense ratio data for MBB is shown on the page when available from our data provider.
What are the largest holdings in MBB?: Top holdings include BLACKROCK CASH CL INST SL AGENCY, USD CASH, GNMA2 30YR TBA(REG C) 5.50% 09/21/2026, FHLMC 30YR UMBS SUPER 2.00% 05/01/2051, UMBS 30YR TBA(REG A) 5.50% 09/14/2026.
How can PortView analyze MBB overlap with other ETFs?: PortView computes the holdings overlap between MBB and the other ETFs and stocks you own, plus your combined sector and geographic exposure, so you can see true diversification.

The information provided by PortView is for informational and educational purposes only and does not constitute investment advice. Market data may be delayed. Past performance does not guarantee future results.