MBB — iShares MBS ETF

MBB Price Performance — Growth of $10,000

Value of a $10,000 investment in MBB over time, compared with SPY. Both lines are rebased to $10,000 on the first shared date. Based on total returns — prices are adjusted for dividends and splits, so this assumes distributions were reinvested. Hover or tap the chart for exact values.

MBB Drawdown

The "underwater" chart: MBB's decline from its highest prior value at each point in time. It shows how deep past losses ran and how long the fund took to recover to break-even.

Overview

The iShares MBS ETF (MBB) operates within the Mortgage-Backed category, where it is one of four funds tracked by ETFValuer. Issued by iShares, the fund manages $39.6 billion in assets and trades at a price of $93.67. It holds an overall rank of #231 out of 458 tracked ETFs across all categories and has received an ETFValuer grade of C with a score of 60.7 out of 100. The fund offers a low cost structure with an expense ratio of 0.04% while providing a dividend yield of 4.26%. The substantial asset under management relative to the small category size suggests significant investor adoption compared to its peers. These metrics collectively define the fund's position as a widely held, cost-efficient vehicle within its specific sector.

Short-term performance shows mixed results with a 1-day return of +0.32% and a 1-week gain of +0.28%, followed by a 1-month decline of -0.97%. The 3-month return of -0.41% and a 6-month return of -0.09% indicate a period of stagnation before the fund posted a year-to-date gain of +0.55%. Over the longer term, the fund has demonstrated stronger growth, recording a 1-year return of +4.94% and a 3-year return of +15.04%. This trajectory reveals a divergence where recent short-term fluctuations have been negative or flat, contrasting with the positive momentum observed over the one and three-year horizons. The data suggests the fund has recovered from intermediate-term losses to achieve positive annualized gains over the past three years.

The fund carries a volatility label of Very Low, yet it exhibits a beta of 1.14, indicating it moves slightly more than the broader market despite its low volatility classification. A Sharpe ratio of -0.01 suggests that the risk-adjusted returns have been negligible over the measured period. The maximum drawdown of -6.79% provides a specific measure of the worst peak-to-trough decline experienced by the fund. This combination of a negative Sharpe ratio and a defined maximum drawdown implies that while the fund may not experience extreme daily swings, it has faced periods where returns did not adequately compensate for the risk taken. The high beta alongside very low volatility suggests the fund's price movements may be sensitive to market shifts even if the overall variance remains contained.

AI-generated summary based on the data on this page.

MBB Top Holdings

Holdings as of 2026-05-31 per the fund's most recent SEC N-PORT-P filing. Top 10 holdings make up 13.1% of net assets — a rough gauge of concentration risk (the higher this figure, the more the fund's return depends on a handful of names). To see how MBB's holdings overlap with other ETFs you own or are considering, check the Stock Overlap tool.

Which Funds Overlap With MBB

Holding two funds that own the same companies adds cost and complexity without adding much diversification. These tracked ETFs share the most names with MBB's top 10 — SPMB overlaps most, holding 4 of the same companies as MBB's top 10 (6.3% of MBB's assets).

Compares the top 10 reported holdings of each fund, so it's a floor on true overlap — two S&P 500 trackers overlap ~100% even when only 10 names are listed. Use the Stock Overlap tool to search by individual company.

Market Backdrop

10-Year Treasury Yield: 4.65% (as of 2026-07-27) — The yield on 10-year US Treasury bonds — the standard "risk-free rate" benchmark used to contextualize this fund’s Sharpe ratio and returns.

CBOE Volatility Index (VIX): 18.67 (as of 2026-07-27) — A real-time gauge of expected S&P 500 volatility over the next 30 days — useful context for this fund’s own volatility label.

Federal Funds Rate: 3.63% (as of 2026-06-01) — The Federal Reserve’s target policy rate, which anchors short-term borrowing costs across the economy.

MBB Liquidity, Domicile & Tax Treatment

Liquidity: Quoted bid/ask spread is 0.31% and average daily volume is 2.1M/day. Tighter spreads and higher volume mean lower round-trip trading costs; this is a live-market snapshot and can widen during volatile sessions. AUM of $39.6B provides ample scale, supporting tight spreads and issuer commitment to keep the fund open.

Domicile & tax treatment: MBB is a US-domiciled, SEC-registered ('40 Act) exchange-traded fund. Dividends and capital gains distributions are reported to US investors on Form 1099-DIV, and the fund is not subject to the PFIC reporting or UCITS-specific rules that apply to Irish- or Luxembourg-domiciled funds. Non-US investors should note that US-domiciled ETFs are generally subject to 30% US withholding tax on dividends (unless reduced by treaty) and to US estate tax exposure on the position — Irish-domiciled UCITS ETFs tracking the same index often avoid both, which is why non-US residents frequently prefer the UCITS equivalent where one exists. This is general information, not tax advice — consult a tax professional for your situation.

MBB Performance History

How MBB Compares to Other Mortgage-Backed ETFs