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MBB · NASDAQ · ETF

iShares MBS ETF (MBB) Price, Holdings & Fees

$406.19−0.10%−$0.40End-of-day price as of Oct 9, 2026

iShares MBS ETF (MBB) closed at $406.19 on Oct 9, 2026, down 0.10% from the previous close of $406.59.

Share price, past year

1Y +31.55%

52-week range $295.70 – $430.55. Daily closing prices.
Monthly closing prices
Last closing price of each month
DateClose
Oct 9, 2026$406.19
Sep 30, 2026$402.90
Aug 31, 2026$406.11
Jul 31, 2026$430.55
Jun 30, 2026$421.79
May 29, 2026$411.57
Apr 30, 2026$373.22
Mar 31, 2026$338.70
Feb 27, 2026$328.56
Jan 30, 2026$313.69
Dec 31, 2025$306.17
Nov 28, 2025$295.70
Oct 31, 2025$303.92

Key statistics

Expense ratio
0.04%
as of Feb 28, 2026
Net assets
$38.7B
as of May 31, 2026
Holdings
11,146
as of May 31, 2026
52-week range
$295.70 – $430.55

iShares MBS ETF's expense ratio is 0.04%: $4.00 a year on $10,000 invested.

Holdings

iShares MBS ETF held 11,146 investments worth $38.74B as of May 31, 2026. Its largest holding was BLACKROCK CASH FUNDS, at 6.77% of the fund.

iShares MBS ETF largest holdings by share of net assets
#Holding% of fundValue
1BLACKROCK CASH FUNDS6.77%$2.62B
2Freddie Mac1.05%$405.59M
3Government National Mortgage Association0.95%$367.08M
4UMBS, TBA0.83%$322.19M
5Government National Mortgage Association0.67%$260.19M
6UMBS, TBA0.64%$249.20M
7Government National Mortgage Association0.55%$212.99M
8Government National Mortgage Association0.54%$209.88M
9Government National Mortgage Association0.53%$206.31M
10Fannie Mae0.52%$202.25M
11Freddie Mac0.50%$194.47M
12Government National Mortgage Association0.46%$176.75M
13Government National Mortgage Association0.45%$176.23M
14Fannie Mae0.44%$171.51M
15Fannie Mae0.44%$169.23M
16Government National Mortgage Association0.41%$158.91M
17Government National Mortgage Association0.36%$140.74M
18Government National Mortgage Association0.35%$137.20M
19UMBS, TBA0.34%$130.47M
20Fannie Mae0.33%$126.68M
21Fannie Mae0.33%$126.62M
22Fannie Mae0.31%$121.26M
23Government National Mortgage Association0.31%$120.37M
24Government National Mortgage Association0.30%$117.13M
25Fannie Mae0.30%$114.62M

Top 25 of 11,146 holdings, as of May 31, 2026. Percentages are of the fund's net assets.

What the fund owns

iShares MBS ETF holdings by asset type
Asset type% of fund
Mortgage-backed securities98.10%
Cash and short-term investments6.77%
iShares MBS ETF holdings by country, largest 1
Country% of fund
United States104.88%

Shares of net assets from the fund's N-PORT report. Funds that borrow can add up to more than 100%, with borrowing (such as repurchase agreements) shown as a negative share.

Monthly total returns

Over the 3 months to May 31, 2026, iShares MBS ETF's total return was −1.27%, as reported to the SEC.

iShares MBS ETF monthly total returns
MonthTotal return
May 31, 2026+0.28%
Apr 30, 2026+0.08%
Mar 31, 2026−1.62%

The fund's own total returns as reported to the SEC (N-PORT), including reinvested distributions. Not the sample prices above.

Fund profile

Name
iShares MBS ETF
Ticker
MBB
Exchange
NASDAQ
Fund type
ETF
Trust
iSHARES TRUST
SEC series ID
S000013702
SEC CIK
0001100663
Fractional shares
Yes

Recent SEC filings

Shareholder reports and prospectuses are filed by iSHARES TRUST, the trust behind iShares MBS ETF, and cover all of its funds.

Frequently asked questions

What is MBB's price?

iShares MBS ETF (MBB) closed at $406.19 on Oct 9, 2026, down 0.10% from the previous close of $406.59.

What is MBB's expense ratio?

iShares MBS ETF's expense ratio is 0.04%: $4.00 a year on $10,000 invested.

What does MBB hold?

iShares MBS ETF held 11,146 investments worth $38.74B as of May 31, 2026. Its largest holding was BLACKROCK CASH FUNDS, at 6.77% of the fund. Its five largest holdings were BLACKROCK CASH FUNDS, Freddie Mac, Government National Mortgage Association, UMBS, TBA, Government National Mortgage Association.

How has MBB performed?

Over the 3 months to May 31, 2026, iShares MBS ETF's total return was −1.27%, as reported to the SEC.

Sources and methodology

Holdings, net assets and monthly returns come from the fund's N-PORT filing with the SEC, as of May 31, 2026 (filed Jul 24, 2026). The expense ratio is from the fund's prospectus or shareholder report, as of Feb 28, 2026. Prices are generated sample data for development. Data sources and disclosures