iShares MBS ETF (MBB) Holdings & Expense Ratio

For informational purposes only. Not financial advice.

Quick Answer

iShares MBS ETF (MBB) has a last stored price of $91.52, as of the Oct 26, 2026 trading session. It has a 0.04% expense ratio and $38.8B in assets under management.

Holdings and weights below are as of Mar 15, 2026. In the stored portfolio snapshot, the largest listed holding is BlackRock Cash Funds Instl SL Agency (BISXX) at 5.90%, and the largest sector allocation is Cash & Others at 100.0%.

iShares MBS ETF (MBB) ETF — Price, Holdings & Analysis

ETF Overview

The iShares MBS ETF (MBB) provides investors with targeted access to the U.S. mortgage-backed securities (MBS) market. MBB tracks an index of investment-grade MBS, offering a diversified portfolio of over 11,141 holdings. This ETF focuses on securities issued and/or guaranteed by U.S. government agencies, providing a level of credit quality. A notable aspect of MBB is its sector allocation, with 100% allocated to Cash & Others. While the fund aims to track U.S. government agency-backed MBS, its country exposure reveals that 94.7% of its holdings are in 'Other' locations, with only 5.3% in the United States. The largest single holding is BlackRock Cash Funds Instl SL Agency (BISXX) at 5.90%. MBB is suitable for investors seeking exposure to the fixed income market, specifically the MBS sector, with a focus on government-backed securities. Past performance does not guarantee future results.

Risk Metrics

MBB, while providing access to mortgage-backed securities, carries certain risks. The fund's country exposure is heavily weighted towards 'Other' at 94.7%, which introduces geographical risk beyond the U.S. market. Although the fund invests in investment-grade mortgage-backed securities, the concentration in a single sector (Cash & Others at 100%) increases sector-specific risk. The fund's beta is 1.12, indicating that it is more volatile than the broader market. With over 11,141 holdings, the fund is well-diversified within its specific asset class, mitigating some concentration risk. The expense ratio of 0.0400% can be considered a low expense drag on returns. Past performance does not guarantee future results.

Beta: 1.12

Expense Ratio

0.04%

What does MBB hold?

Holding	Weight
BlackRock Cash Funds Instl SL Agency (BISXX)	5.90%

Holdings and weights as of Mar 15, 2026. This fund data is more than 45 days old; verify current holdings with the issuer.

How Is the Fund Allocated?

Sector	Weight
Cash & Others	100.0%

Country	Weight
Other	94.7%
United States	5.3%

Dividend Yield

4.12%

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iShares Climate Conscious & Transition MSCI USA ETF (USCL) (Equity) — 0.08% expense ratio

Questions & Answers

What is MBB and what does it track?

The iShares MBS ETF (MBB) is a fixed-income ETF designed to track the investment results of an index composed of investment-grade mortgage-backed pass-through securities. These securities are issued and/or guaranteed by U.S. government agencies, providing a level of credit quality.

MBB holds a large portfolio of over 11,141 securities, offering diversified exposure to the MBS market.

What is the expense ratio for MBB?

The iShares MBS ETF (MBB) has an expense ratio of 0.0400%. This means that for every $10,000 invested in the fund, $4.00 is used to cover the fund's operating expenses.

The expense ratio is relatively low compared to the category average for fixed income ETFs, which can be around 0.44%.

What are the top holdings in MBB?

The iShares MBS ETF (MBB) has a diversified portfolio of over 11,141 holdings. The top holding is BlackRock Cash Funds Instl SL Agency (BISXX), representing 5.90% of the fund's total assets.

The fund's description indicates a focus on investment-grade mortgage-backed securities issued or guaranteed by U.S. government agencies.

Is MBB a good long-term investment?

Whether MBB is a suitable long-term investment depends on an investor's individual circumstances and risk tolerance. MBB provides exposure to the mortgage-backed securities market, with a focus on investment-grade securities backed by U.S. government agencies.

The fund has a low expense ratio of 0.0400% and a dividend yield of 4.12%.

How does MBB compare to similar ETFs?

MBB competes with other ETFs that focus on mortgage-backed securities. A key differentiator is MBB's large AUM of $38.84B, indicating its popularity and liquidity. Its expense ratio of 0.0400% is competitive within the category.

Other similar ETFs may have different index tracking methodologies, credit quality focuses, or expense ratios.

Does MBB pay dividends?

Yes, the iShares MBS ETF (MBB) distributes dividends to its shareholders. The current dividend yield for MBB is 4.12%. It's important to note that dividend yields can fluctuate based on market conditions and the fund's underlying holdings.

Investors seeking income may find MBB attractive due to its dividend payouts. Past performance does not guarantee future results.

Disclaimer: This content is for informational purposes only and does not constitute investment advice. Always do your own research and consult a financial advisor.

Data provided for informational purposes only.

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