MUB Short Interest
iShares National Muni Bond ETF (MUB) operates in the Financial Services sector, specifically the Asset Management - Bonds industry, with a market capitalization near $46.15B, listed on AMEX, carrying a beta of 0.90 to the broader market. This exchange-traded fund is designed to closely replicate the performance of a designated index, which exclusively comprises high-quality municipal bonds issued across the United States. public since 2007-09-10.
Short interest is the total number of shares currently sold short and not yet covered, reported bi-monthly by FINRA. Days to cover (short interest divided by average daily volume) indicates how long it would take short sellers to close positions, with higher values signaling greater squeeze potential.
- Settlement Date
- 2026-07-31
- Short Interest
- 6.1M
- Previous Short Interest
- 5.6M
- Change
- 9.38%
- Days to Cover
- 1.29
- Avg Daily Volume
- 4.7M
- Avg Days to Cover (24 reports)
- 1.77
Showing 24 bi-monthly FINRA short interest reports for iShares National Muni Bond ETF.
Learn how short interest is reported and how to read the data →
MUB most-active contracts
| Type | Strike | Expiration | Volume | OI | IV | Bid | Ask |
|---|---|---|---|---|---|---|---|
| PUT | $107.00 | Aug 21, 2026 | 0 | 5.0K | 950.9% | $1.05 | $1.45 |
| PUT | $106.00 | Aug 21, 2026 | 1 | 11.7K | 607.6% | $0.15 | $0.40 |
| CALL | $106.00 | Sep 18, 2026 | 2 | 7.5K | 584.6% | $0.20 | $0.50 |
| PUT | $105.00 | Sep 18, 2026 | 0 | 7.5K | 293.2% | $0.25 | $0.45 |
Top 4 contracts from the institutional-grade nightly options scan; ranked by volume within the broader S&P 500/400/600 + ETF universe.
Frequently asked MUB short interest questions
- What is the current MUB short interest?
- As of the Jul 31, 2026 settlement, iShares National Muni Bond ETF (MUB) short interest is 6.1M shares, a +9.38% change from the prior period. FINRA publishes short interest twice monthly on the 15th and last business day of each month under Rule 4560.
- What is the MUB days-to-cover ratio?
- Days-to-cover is 1.29, calculated as short interest divided by average daily volume. It estimates how many trading days closing all short positions would consume given typical liquidity. Values above 5 days are commonly cited as elevated; values above 10 days are squeeze-relevant.
- How does MUB short interest affect options pricing?
- High short interest changes options pricing through three mechanics: borrow-rebate effects (synthetic long stock trades below frictionless put-call parity by approximately the borrow rebate when shares are hard-to-borrow), gamma-squeeze setup risk (if dealers are short gamma against retail call buying, dealer hedge flow can amplify upward moves), and elevated event-vol pricing on names with squeeze potential. See the canonical short-interest documentation for the full mechanism.