CPST Calamos S&P 500 ® Structured Alt Protection ETF - September
Absorbs the whole loss on SPY and caps the gain at 8.0%, over a period ending Sep 1, 2027
As of Sep 12, 2026, CPST sits between its buffer and its cap, with SPY up 0.3% since the period began.
Key facts
365th of 380 buffer ETFs by how soon they reset
In plain words
354 days remained on Sep 12, 2026. On Sep 1, 2027 the period ends and a new cap is set.
| Reference index | SPY |
|---|---|
| Buffer | 100% |
| Outcome period | Sep 1, 2026 to Sep 1, 2027 |
| Starting cap | +8.0% |
| SPY return since period start | +0.3% |
| Fund return since period start | −0.1% |
| Net assets (source, as filed for Apr 30, 2026) | $32m |
| Band state today (ETFIQ) | Open |
| Can still gain (issuer, fund price) | not published |
| Fall before buffer (issuer, fund price) | 0.0% |
| Fall to the buffer in index terms (ETFIQ) | 0.3% |
| Protection left in index points (ETFIQ) | 100.0% of 100.0% |
| Days left in period | 354 |
| Expense ratio (issuer page, Sep 12, 2026) | 0.69% |
Issuer-published figures as of the date shown; ETFIQ calculations marked. Definitions on the learn page. How these figures are computed
Questions people ask
- How far can CPST fall before the buffer helps?
- 0.0% in fund-price terms on Sep 12, 2026, by the issuer's figure. In index terms SPY can fall 0.3% from that level before the buffer begins. Losses until that point are the holder's.
- How much of the CPST buffer is left?
- 100.0% of the 100.0% buffer sat below the SPY level on Sep 12, 2026. That is an ETFIQ calculation in index points, on one definition for every issuer.
- When does CPST reset?
- The outcome period ends on Sep 1, 2027, 354 days from the data on Sep 12, 2026. A new cap is set the next day and the buffer starts again.
- What does CPST cost?
- The prospectus expense ratio is 0.69% a year.
The words on this page
- Buffer
- The first slice of loss the fund absorbs for you over its outcome period, stated on the reference index. A 15% buffer means the index can fall 15% before you take any of it.
- Cap
- The most the fund can return over the period, however far the index rises. It is the price paid for the buffer.
- Outcome period
- The window the buffer and cap apply over, usually a year. Both are set at the start and only hold if you are there for the whole of it.
- Reset
- The day one outcome period ends and the next begins, with a fresh buffer and a fresh cap struck at that day’s level.
- Protection left
- The part of the buffer still below today’s index level. A buffer bought mid-period is not the full buffer; this is what is left of it.
Every term used here, defined in full on the buffer ETFs vocabulary page.
Where these figures came from
ETFIQ links to the documents behind every figure. It is not affiliated with any issuer, and a link is not an endorsement.
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Cite this page. ETFIQ, CPST, buffer ETFs, data as of Sep 12, 2026. https://etfiq.com/funds/CPST Free to use with attribution; the underlying files are at Open data.