FSLY · Fastly, Inc. · Short Interest
10 customers — 32% of revenue (trailing 12 month periods ended March 31, 2026)
“Our 10 largest customers generated an aggregate of 32% of our revenue for each of the trailing 12 month periods ended March 31, 2026 and 2025.”
Key customers — 10% of revenue (trailing 12 month period ended March 31, 2026)
“Affiliated customers that are business units of a single company generated an aggregate of 10% and 9% of our revenue for the trailing 12 month periods ended March 31, 2026 and 2025, respectively.”
Shares sold short and not yet covered, reported twice monthly. Days to cover is the reported short position divided by average daily volume.
FSLY Latest Reported Short Interest
FINRA reported 21,187,254 FSLY shares sold short as of the September 30, 2026 settlement date, a decrease of 377,900 shares. Days to cover was 2.06 based on FINRA's reported average daily volume.
Official FINRA short-interest data · share counts are restated for subsequent splits of this listing
FSLY Short Interest Forecast
Equibles' model estimates 21,890,938 shares sold short for the October 15, 2026 settlement, +3.3% versus the latest reported position, with a likely range of 19,455,562 to 24,681,276 shares. This model prediction uses FINRA data through October 15, 2026; FINRA's official release is expected October 26, 2026.
Expected Oct 15 short interest
as of Oct 15 Medium confidence 57% chance it risesPositioning score 59.2 + catalyst boost 0 (total capped at 100). This is a screening index, not a probability of a squeeze.
Method and coverage limits
Factor percentiles compare eligible primary operating-company stocks reporting short interest at the latest settlement date (2026-09-30). The weighted mean uses short interest 30%, days to cover 20%, price vs VWAP 15%, short-volume trend 15%, short-interest change 10%, and fails-to-deliver 10%. Missing factors redistribute their weight; incomplete coverage is not evidence of low risk. Price, volume, and earnings boosts add 10 each, capped at 20.
Shares outstanding are not free float. Borrow fees, utilization, lendable supply, recalls, and dealer inventory are not measured. Short-sale volume does not measure the change in open shorts; fails to deliver are not a borrow-cost measurement; price vs VWAP does not establish short sellers' entry prices. Earnings can move prices in either direction.
The weights are judgment-based, not calibrated to future squeeze outcomes. The separate options assessment below does not change this universe ranking.
Options positioning & squeeze sensitivity
Nearest expiration after today within 30 calendar days; same-day expirations and later maturities are excluded.
Open interest is incomplete, stale, or dated inconsistently; positioning totals are unavailable.
Open interest has both a buyer and a seller; it does not reveal dealer hedge direction. Gross gamma sums both calls and puts without netting and uses a local 1% price-change approximation. It measures sensitivity, not predicted buying or a squeeze probability.
Assessment prepared 2026-10-24 12:04 UTC. Options model values may come from a cached snapshot; their original computation time is not supplied. Open interest has its own effective date.
Short Interest History
| Settlement Date | Current Position | Previous Position | Change | Days to Cover |
|---|---|---|---|---|
|
2026-10-30
Scheduled
FINRA publishes Nov 10
|
— | — | — | — |
|
2026-10-15
Scheduled
FINRA publishes Oct 26
|
— | — | — | — |
| 2026-09-30 | 21,187,254 | 21,565,154 | -377,900 | 2.06 |
| 2026-09-15 | 21,565,154 | 20,213,781 | +1,351,373 | 3.95 |
| 2026-08-31 | 20,213,781 | 21,437,861 | -1,224,080 | 4.36 |
| 2026-08-14 | 21,437,861 | 22,594,904 | -1,157,043 | 2.61 |
| 2026-07-31 | 22,594,904 | 25,531,692 | -2,936,788 | 4.48 |
| 2026-07-15 | 25,531,692 | 25,354,952 | +176,740 | 6.36 |
| 2026-06-30 | 25,354,952 | 18,671,252 | +6,683,700 | 4.41 |
| 2026-06-15 | 18,671,252 | 19,665,563 | -994,311 | 2.38 |
| 2026-05-29 | 19,665,563 | 21,261,305 | -1,595,742 | 3.24 |
| 2026-05-15 | 21,261,305 | 18,942,162 | +2,319,143 | 1.48 |
| 2026-04-30 | 18,942,162 | 19,606,464 | -664,302 | 2.27 |
| 2026-04-15 | 19,606,464 | 18,354,032 | +1,252,432 | 1.15 |
| 2026-03-31 | 18,354,032 | 17,844,166 | +509,866 | 1.46 |
| 2026-03-13 | 17,844,166 | 16,042,418 | +1,801,748 | 1.38 |
| 2026-02-27 | 16,042,418 | 17,089,599 | -1,047,181 | 1.09 |
| 2026-02-13 | 17,089,599 | 13,901,854 | +3,187,745 | 1.00 |
| 2026-01-30 | 13,901,854 | 14,553,610 | -651,756 | 3.87 |
| 2026-01-15 | 14,553,610 | 12,710,597 | +1,843,013 | 4.53 |
| 2025-12-31 | 12,710,597 | 12,519,104 | +191,493 | 5.09 |
| 2025-12-15 | 12,519,104 | 9,445,148 | +3,073,956 | 1.88 |
| 2025-11-28 | 9,445,148 | 9,984,826 | -539,678 | 2.34 |
| 2025-11-14 | 9,984,826 | 10,683,654 | -698,828 | 1.50 |
| 2025-10-31 | 10,683,654 | 10,404,710 | +278,944 | 5.36 |
Full FINRA short interest reporting calendar