CPST vs SEPT: Cap, Buffer & Days Left
As of Oct 13, 2026 SEPT can fall 2.0% before its buffer engages and CPST 0.5%. Net assets on Oct 12, 2026: $41m for Calamos S&P 500 ® Structured Alt Protection ETF - September and $38m for AllianzIM U.S. Equity Buffer10 ETF - Sep.
CPST costs 0.05 points a year less; their one-year returns differ by 8.7 points.
Points (pts) are percentage points.
| CPST | SEPT | |
|---|---|---|
| Expense ratio | 0.69% | 0.74% |
| Net assets, as of Oct 12, 2026 | $41m | $38m |
| Total return, 1 year | +5.7% | +14.4% |
| What it tracks | SPY | SPY |
| Holdings in common | not published | |
| Index fall to the buffer | 2.1% | 1.3% |
CPST: reference +2.1% since period start, fund +0.5%; buffer Floor; cap +8.1%; Full floor. Figures to Oct 13, 2026.
Figures to Oct 13, 2026.
SEPT: reference +1.3% since period start, fund +1.3%; buffer 0 to −10; cap +17.5%; Between buffer and cap. Figures to Oct 13, 2026.
SEPT: reference +1.3% since period start, fund +1.3%; buffer 0 to −10; cap +17.5%; Between buffer and cap. Figures to Oct 13, 2026.
These are two different products. CPST is a floor fund, which caps how far a holder can fall. SEPT is a buffer fund, which absorbs the first part of a fall and leaves everything below it with the holder.
Where each one stands today
CPST resets first, on Aug 31, 2027, 322 days from now; SEPT runs to Aug 31, 2027, 322 days. A fall from here reaches CPST’s buffer after 0.5% and SEPT’s after 2.0%. Both track SPY, so what separates them is where each is in its own period.
Performance, window by window
| Total return | Gap to the reference's price return | |||
|---|---|---|---|---|
| Window | CPST | SEPT | CPST | SEPT |
| 3 months | +1.3% | +3.2% | −2.6 pts | −0.7 pts |
| 6 months | +3.4% | +9.1% | −10.0 pts | −4.3 pts |
| 1 year | +5.7% | +14.4% | −13.4 pts | −4.8 pts |
| 3 years | not published | +59.8% | not published | −20.6 pts |
| Since launch Not the same days: CPST Sep 2024 · SEPT Sep 2023 | +14.1% | +55.1% | −26.8 pts | −17.3 pts |
Each fund's gap is to its reference's price return, dividends left out: the basis the outcome period uses. Source: ETFIQ. Open this comparison in the app →
On the same fields
As of Oct 13, 2026. Source: ETFIQ.
About CPST
The fund's price can fall 0.5% from here before the buffer starts absorbing losses, by the issuer's figure. In index terms, SPY can fall 2.1% from today's level to the point where the buffer begins. Protection left, in index points: 100.0% of the 100.0% buffer still sits below today's SPY level. 322 days remained on Oct 13, 2026. On Aug 31, 2027 the period ends and a new cap is set.
About SEPT
From its price on Oct 13, 2026, the fund can gain about 15.3% more before it reaches its cap. The fund's price can fall 2.0% from here before the buffer starts absorbing losses, by the issuer's figure. In index terms, SPY can fall 1.3% from today's level to the point where the buffer begins. Protection left, in index points: 10.0% of the 10.0% buffer still sits below today's SPY level.
Questions people ask
ETFIQ links to the documents behind every figure; a link is not an endorsement. A comparison is not a recommendation.
How this is computed
ETFIQ calculates every figure from each issuer’s published outcome-period terms. Buffer ETFs hold options on an index, not shares, so there is no holdings overlap to report.
Every figure is an ETFIQ calculation with distributions reinvested.
Cite this pageCitation, APA and Markdown
ETFIQ, CPST against SEPT, data as of Oct 13, 2026. https://etfiq.com/compare/buffer/cpst-vs-sept
ETFIQ. (Oct 13, 2026). CPST against SEPT. Retrieved from https://etfiq.com/compare/buffer/cpst-vs-sept
[CPST against SEPT (ETFIQ, Oct 13, 2026)](https://etfiq.com/compare/buffer/cpst-vs-sept)
Free to use with attribution for figures ETFIQ computes; issuer data stays under its owner's terms.