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HowShorted

MBB short interest Nasdaq Global Market

iShares MBS ETF. FINRA's reported shares short for this symbol, twice a month by settlement date, shown as the regulator publishes them. No percentage is shown: no SEC filer maps to the symbol (funds, notes, preferreds, warrants and foreign listings).

Shares short
6,572,541
vs previous settlement
+3,258,326 (+98.3%)
days to cover
2.55
Settlement date
15 Sep 2026

Shares short over time

Aggregate net short position time series for MBB shares short

Days to cover

FINRA's own figure: reported shares short divided by the security's average daily trading volume, published alongside each settlement.

Aggregate net short position time series for MBB days to cover

Fails to deliver

The SEC's fails-to-deliver figure for MBB: the aggregate net balance of shares that failed to be delivered at each settlement date, published by the SEC twice a month and shown here verbatim for the trailing window. A balance is not a daily flow, and a fail has many ordinary causes; the SEC says it cannot guarantee the accuracy of the data. See what fails to deliver are and the largest balances today.

Latest balance
2,657
14 Sep 2026
Highest in window
895,014
14 Nov 2025
Days with a balance
96
Window
16 Sep 2025 to 14 Sep 2026
Aggregate net short position time series for iShares MBS ETF fails to deliver

Source: U.S. Securities and Exchange Commission, fails-to-deliver data (public domain). Only settlement days with a positive balance appear; the largest balance in the window was 895K shares.

History

Every FINRA settlement we hold for MBB, newest first. สณ marks a figure FINRA itself flagged as revised.

Full reported short interest history
Settlement dateShares shortChangeDays to cover
15 Sep 20266,572,541+3,258,3262.55
31 Aug 20263,314,215+1,360,0571.00
14 Aug 20261,954,158โˆ’400,2031.03
31 Jul 20262,354,361+184,1071.14
15 Jul 20262,170,254โˆ’61,2361.11
30 Jun 20262,231,490โˆ’768,4911.13
15 Jun 20262,999,981โˆ’220,2731.25
29 May 20263,220,254+539,8951.17
15 May 20262,680,359+902,5741.36
30 Apr 20261,777,785+267,8451.00
15 Apr 20261,509,940+251,2811.00
31 Mar 20261,258,659โˆ’377,9991.00
13 Mar 20261,636,658โˆ’1,547,7361.00
27 Feb 20263,184,394โˆ’84,4081.59
13 Feb 20263,268,802+1,476,2701.19
30 Jan 20261,792,532โˆ’1,423,7311.00
15 Jan 20263,216,263โˆ’451,2661.00
31 Dec 20253,667,529+214,2781.83
15 Dec 20253,453,251โˆ’774,1341.34
28 Nov 20254,227,385+782,6901.33
14 Nov 20253,444,695โˆ’325,4031.00
31 Oct 20253,770,098+60,5551.00
15 Oct 20253,709,543โˆ’2,202,8351.00
30 Sep 20255,912,378+1,834,4161.59
15 Sep 20254,077,962+998,3631.56
29 Aug 20253,079,599โˆ’1,552,6871.11
15 Aug 20254,632,286+3,112,7121.76
31 Jul 20251,519,574โˆ’6,591,0321.00
15 Jul 20258,110,606+3,251,0152.96
30 Jun 20254,859,591โˆ’2,772,0551.94
13 Jun 20257,631,646+1,390,3662.83
30 May 20256,241,280+4,110,4481.97
15 May 20252,130,832โˆ’119,9841.00
30 Apr 20252,250,816โˆ’1,060,7801.00
15 Apr 20253,311,596+1,839,3491.01
31 Mar 20251,472,247+902,2121.00
14 Mar 2025570,035โˆ’776,4161.00
28 Feb 20251,346,451โˆ’260,4471.00
14 Feb 20251,606,898+896,1091.00
31 Jan 2025710,789โˆ’657,4491.00
15 Jan 20251,368,238โˆ’421,4351.00
31 Dec 20241,789,673โˆ’849,5141.00
13 Dec 20242,639,187โˆ’281,1881.00
29 Nov 20242,920,375+915,0131.00
15 Nov 20242,005,362+837,1201.00
31 Oct 20241,168,242โˆ’1,495,4861.00
15 Oct 20242,663,728+566,7341.03
30 Sep 20242,096,994โˆ’3,103,7921.00
13 Sep 20245,200,786+2,735,5952.73
30 Aug 20242,465,191โˆ’509,3981.58
15 Aug 20242,974,589+883,8991.41
31 Jul 20242,090,690โˆ’3,526,1631.07
15 Jul 20245,616,853+2,994,5413.10
28 Jun 20242,622,312โˆ’595,8291.86
14 Jun 20243,218,141+1,314,8471.51
31 May 20241,903,294โˆ’2,777,0061.10
15 May 20244,680,300+1,298,1142.01
30 Apr 20243,382,186+1,716,0511.00
15 Apr 20241,666,135โˆ’96,6561.00
28 Mar 20241,762,791+438,0861.00
15 Mar 20241,324,705โˆ’1,969,3631.00
29 Feb 20243,294,068+2,288,4011.01
15 Feb 20241,005,667โˆ’688,0571.00
31 Jan 20241,693,724โˆ’50,3681.00
12 Jan 20241,744,092+969,0691.00
29 Dec 2023775,023โˆ’166,9801.00
15 Dec 2023942,003โˆ’2,026,7571.00
30 Nov 20232,968,760โˆ’184,5621.05
15 Nov 20233,153,322โˆ’1,188,6111.41
31 Oct 20234,341,933+100,2221.09
13 Oct 20234,241,711+1,778,9571.68
29 Sep 20232,462,754+440,8261.05
15 Sep 20232,021,928+1,055,6241.26
31 Aug 2023966,304+89,0361.00
15 Aug 2023877,268+328,0311.00
31 Jul 2023549,237โˆ’409,6741.00
14 Jul 2023958,911+228,6271.00
30 Jun 2023730,284โˆ’405,7201.00
15 Jun 20231,136,004โˆ’2,181,7391.00
31 May 20233,317,743+116,1992.15
15 May 20233,201,544+1,041,3621.91
28 Apr 20232,160,182โˆ’382,0791.30
14 Apr 20232,542,261โˆ’1,739,6971.22
31 Mar 20234,281,958+411,5072.14
15 Mar 20233,870,451โˆ’3,314,2551.15
28 Feb 20237,184,706โˆ’1,644,8143.73
15 Feb 20238,829,520+57,5154.31
31 Jan 20238,772,005+4,712,5502.52
13 Jan 20234,059,455+2,674,3401.05
30 Dec 20221,385,115โˆ’306,5281.00
15 Dec 20221,691,643+80,0071.00
30 Nov 20221,611,636โˆ’2,355,1291.00
15 Nov 20223,966,765โˆ’1,850,8081.71
31 Oct 20225,817,573โˆ’1,813,4381.00
14 Oct 20227,631,011+3,117,9703.38
30 Sep 20224,513,041+2,011,9311.77
15 Sep 20222,501,110โˆ’119,2831.34
31 Aug 20222,620,393+904,9362.46
15 Aug 20221,715,457โˆ’2,919,0521.00
29 Jul 20224,634,509+319,8002.84
15 Jul 20224,314,709+466,3922.68
30 Jun 20223,848,317โˆ’686,5011.37
15 Jun 20224,534,818+3,016,1821.53
31 May 20221,518,636+107,0921.00
13 May 20221,411,544โˆ’2,975,3581.00
29 Apr 20224,386,902+2,822,0401.99
14 Apr 20221,564,862โˆ’1,093,4151.00
31 Mar 20222,658,277+1,194,3231.58
15 Mar 20221,463,954โˆ’2,299,8741.00
28 Feb 20223,763,828+1,012,6462.17
15 Feb 20222,751,182+766,7471.00
31 Jan 20221,984,435โˆ’1,758,5651.00
14 Jan 20223,743,000+844,9751.76
31 Dec 20212,898,025+216,9212.19
15 Dec 20212,681,104โˆ’117,8531.53
30 Nov 20212,798,957+757,5281.99
15 Nov 20212,041,429+78,3371.15
29 Oct 20211,963,092โˆ’1,822,0161.00
15 Oct 20213,785,108โˆ’633,2822.05
30 Sep 20214,418,390โˆ’1,123,7894.61
15 Sep 20215,542,179+819,2384.80
31 Aug 20214,722,941โˆ’634,6844.56
13 Aug 20215,357,625โˆ’1,005,3083.33
30 Jul 20216,362,933+657,8943.40
15 Jul 20215,705,039+1,230,1382.86
30 Jun 20214,474,901+2,537,7821.94
15 Jun 20211,937,119สณ+373,2132.05
28 May 20211,563,906+765,9851.47
14 May 2021797,921+82,2791.00
30 Apr 2021715,642โˆ’25,1291.00
15 Apr 2021740,771โˆ’264,7111.00
31 Mar 20211,005,482โˆ’1,688,9891.00
15 Mar 20212,694,471โˆ’1,656,0732.02
26 Feb 20214,350,544+784,4302.91
12 Feb 20213,566,114+325,7732.88
29 Jan 20213,240,341+1,180,7952.10
15 Jan 20212,059,546โˆ’343,3831.00
31 Dec 20202,402,929โˆ’321,8771.72
15 Dec 20202,724,806+791,9761.67
30 Nov 20201,932,830โˆ’3,558,5581.01
13 Nov 20205,491,388+4,673,8064.62
30 Oct 2020817,582โˆ’1,284,1681.00
15 Oct 20202,101,750โˆ’1,182,0881.00
30 Sep 20203,283,838+1,093,3183.09
15 Sep 20202,190,520+439,5172.41
31 Aug 20201,751,003โˆ’1,457,2181.17
14 Aug 20203,208,221+1,852,9801.85
31 Jul 20201,355,241โˆ’520,8831.43
15 Jul 20201,876,124+418,8382.19
30 Jun 20201,457,286โˆ’780,0321.58
15 Jun 20202,237,318+1,609,1641.12
29 May 2020628,154+256,6751.00
15 May 2020371,479โˆ’69,8581.00
30 Apr 2020441,337+219,8271.00
15 Apr 2020221,510โˆ’68,6831.00
31 Mar 2020290,193+36,6871.00
13 Mar 2020253,506โˆ’139,3531.00
28 Feb 2020392,859โˆ’233,2921.00
14 Feb 2020626,151โˆ’1,169,7361.00
31 Jan 20201,795,887โˆ’628,9311.00
15 Jan 20202,424,818โˆ’470,5941.00
31 Dec 20192,895,412+2,108,7311.43
13 Dec 2019786,681+20,7591.00
29 Nov 2019765,922+108,7241.00
15 Nov 2019657,198โˆ’175,2201.00
31 Oct 2019832,418+477,2481.00
15 Oct 2019355,170โˆ’43,7251.00
30 Sep 2019398,895โˆ’205,2721.00
13 Sep 2019604,167+258,9651.00
30 Aug 2019345,202โˆ’191,7611.00
15 Aug 2019536,963+129,7061.00
31 Jul 2019407,257โˆ’764,1841.00
15 Jul 20191,171,441+534,8461.00
28 Jun 2019636,595โˆ’298,2921.00
14 Jun 2019934,887+306,9051.00
31 May 2019627,982+195,3861.00
15 May 2019432,596โˆ’39,1241.00
30 Apr 2019471,720โˆ’571,9381.00
15 Apr 20191,043,658+857,4811.00
29 Mar 2019186,177โˆ’64,2321.00
15 Mar 2019250,409โˆ’50,0881.00
28 Feb 2019300,497โˆ’1,861,6901.00
15 Feb 20192,162,187+1,966,3531.00
31 Jan 2019195,834โˆ’798,1221.00
15 Jan 2019993,956+540,6331.00
31 Dec 2018453,323โˆ’364,8341.00
14 Dec 2018818,157+479,8681.00
30 Nov 2018338,289โˆ’95,0031.00
15 Nov 2018433,292+16,0451.00
31 Oct 2018417,247โˆ’21,1291.00
15 Oct 2018438,376+46,3561.00
28 Sep 2018392,020โˆ’95,4961.00
14 Sep 2018487,516+215,1711.00
31 Aug 2018272,345โˆ’17,3931.00
15 Aug 2018289,738โˆ’42,0141.00
31 Jul 2018331,752โˆ’398,9521.00
13 Jul 2018730,704+138,5081.00
29 Jun 2018592,196+425,8521.00
15 Jun 2018166,344โˆ’547,3751.00
31 May 2018713,719+506,2501.19
15 May 2018207,469+13,2281.00
30 Apr 2018194,241+23,7201.00
13 Apr 2018170,521+46,0741.00
29 Mar 2018124,447โˆ’36,9831.00
15 Mar 2018161,430โˆ’38,1871.00
28 Feb 2018199,617โˆ’2,0531.00
15 Feb 2018201,670+63,9611.00
31 Jan 2018137,709โˆ’29,8541.00
12 Jan 2018167,563โˆ’117,5081.00
29 Dec 2017285,071โ€“1.00

Scroll inside the table for earlier settlements, back to 29 Dec 2017.

Questions

Frequently asked questions

What is MBB's short interest?
6,572,541 shares short for settlement date 15 Sep 2026, per FINRA's consolidated short interest report, up 3,258,326 from the previous settlement.
Why is there no percentage for MBB?
Because no defensible share count exists to divide by: no SEC filer maps to the symbol (funds, notes, preferreds, warrants and foreign listings). No SEC filer maps to this symbol in EDGAR's ticker file. That is the normal case for funds, exchange-traded notes, preferred shares, warrants, units and foreign listings, none of which file a share count we could divide by.
What is MBB's days to cover?
2.55 days for settlement date 15 Sep 2026: FINRA's own short interest ratio, the reported shares short divided by average daily trading volume, published in the same file and shown verbatim. We hold no volume data ourselves.
Is this the short float?
No. This page shows FINRA's share count only. Short float divides that count by the public float, and short interest as we publish it elsewhere divides it by shares outstanding from SEC filings. Neither denominator is available for this line, so neither ratio is shown.
How often does this update?
FINRA member firms report short positions as of the 15th and the last business day of each month, and FINRA publishes the consolidated figures about nine business days later. We ingest each file the day it appears and re-read recent settlements for revisions.

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