Which resets first, AIOO or CPST?

AIOO ends its outcome period on Dec 31, 2026 and CPST on Sep 1, 2027. A new cap is set the day after each.

Which is cheaper, AIOO or CPST?

AIOO charges 0.64% a year and CPST charges 0.69%, so AIOO is cheaper. Fees come from each fund's prospectus.

AIOO vs CPST: which one stands where?

As of Oct 1, 2026 CPST can fall 0.1% before its buffer engages and AIOO 0.0%, and AIOO resets 243 days sooner. AllianzIM U.S. Equity Buffer100 ETF - Jan and Calamos S&P 500 ® Structured Alt Protection ETF - September.

AIOONo cap

AIOO: reference 0.0% since period start, fund 0.0%; buffer Floor; no cap; No cap.

CPSTFull floor

CPST: reference +0.1% since period start, fund 0.0%; buffer −0 to floor; cap +8.0%; Full floor.

AIOO has no cap. It takes 30% of whatever the index does, where CPST takes all of the rise up to 8.0% and nothing above it.

They do not reset together. AIOO has 92 days of its period left and CPST has 335, so the two are not the same bet on the same months.

Where each one stands today

AIOO resets first, on Dec 31, 2026, 92 days from now; CPST runs to Sep 1, 2027, 335 days. A fall from here reaches AIOO’s buffer after 0.0% and CPST’s after 0.1%. Both track SPY, so what separates them is where each is in its own period.

Every figure is ETFIQ’s own, from the issuer’s published outcome-period terms. A buffer ETF holds FLEX options on its reference index rather than shares, so there is no holdings overlap between two of them to report.

Performance, window by window

	Total return		Gap to the reference
Window	AIOO	CPST	AIOO	CPST
3 months	+0.4%	+1.0%	−2.1 pts	−1.5 pts
6 months	+2.9%	+3.9%	−14.1 pts	−13.0 pts
1 year	+3.6%	+5.2%	−12.1 pts	−10.5 pts

AIOO and CPST over each window. Every figure is an ETFIQ calculation with distributions reinvested. Source: ETFIQ. Open the live comparison on ETFIQ →

On the same fields

AIOO

AllianzIM U.S. Equity Buffer100 ETF - Jan · Absorbs the whole loss on SPY and does not cap the gain, over a period ending Dec 31, 2026

CPST

Calamos S&P 500 ® Structured Alt Protection ETF - September · Absorbs losses from 0.0% to 100.0% on SPY and caps the gain at 8.0%, over a period ending Sep 1, 2027

Issuer AllianzIM Calamos

Reference index SPY SPY

Buffer 100% 0% to 100%

Outcome period Oct 1, 2026 to Dec 31, 2026 Sep 1, 2026 to Sep 1, 2027

Days left 92 335

Starting cap uncapped +8.0%

Can still gain uncapped not published

Fall before buffer 0.0% 0.1%

Protection left, index points 100.0% of 100.0% 100.0% of 100.0%

Index return this period 0.0% +0.1%

Fund return this period 0.0% 0.0%

State today Uncapped Open

Expense ratio 0.64% 0.69%

Net assets $50m $37m

AIOO and CPST on the same fields, as of Oct 1, 2026. Source: ETFIQ.

AIOO in plain words

This fund has no cap. It takes a share of any further rise in SPY. Protection left, in index points: 100.0% of the 100.0% buffer still sits below today's SPY level. 92 days remained on Oct 1, 2026. On Dec 31, 2026 the period ends and a new cap is set.

CPST in plain words

The fund's price can fall 0.1% from here before the buffer starts absorbing losses, by the issuer's figure. In index terms, SPY can fall 0.1% from today's level to the point where the buffer begins. 335 days remained on Oct 1, 2026. On Sep 1, 2027 the period ends and a new cap is set.

Questions people ask

Which resets first, AIOO or CPST?: AIOO ends its outcome period on Dec 31, 2026 and CPST on Sep 1, 2027. A new cap is set the day after each.
Which is cheaper, AIOO or CPST?: AIOO charges 0.64% a year and CPST charges 0.69%, so AIOO is cheaper. Fees come from each fund's prospectus.

Other comparisons

AIOO vs APOC AIOO vs BOCT AIOO vs DDFO AIOO vs DDSQ CPST vs BALT CPST vs DDFO CPST vs AOCT CPST vs APOC

SPDR® S&P 500® ETF Trust →AIOO on its own →CPST on its own →How every figure is computed →Standards and sources →

Where these figures came from

AIOO filings on SEC EDGAR ↗AllianzIM page for AIOO ↗CPST filings on SEC EDGAR ↗Calamos website ↗

ETFIQ links to the documents behind every figure. It is not affiliated with any issuer, and a link is not an endorsement. A comparison is not a recommendation.

Cite this page

ETFIQ, AIOO against CPST, data as of Oct 1, 2026. https://etfiq.com/compare/buffer/aioo-vs-cpst

Open data

Free to use with attribution. Every figure is calculated from a named public source; the method is at etfiq.com/methodology.