They are probably not going to be implemented using long put positions, but a product with a similar return profile to what you're looking for is a buffered ETF. Basically, over a defined period, you agree to a maximum possible downside in exchange for a capped upside. They are available in ETF form from a number of providers.

For example, you could have an S&P 500 fund that, over the next year, will have a maximum of 0% capital losses (it can't go down), you will only get the first, say, 5% of gains that the equity index makes. So if stocks go up 20% the next year, your return is capped at 5%, but if they crash 50%, you don't absorb any capital losses. In practice, the return cap is going to be just a bit above the corresponding Treasury bill for the same duration.

These can be constructed in various different ways and institutionally I'm sure there are more bespoke ways that are more efficient from a fees/returns and tax perspective, but one way to do this on your own without going the ETF route is:

- Pick an amount you'd like to invest. - Buy a Treasury bill for some duration. Treasury bills are discounted at the time of purchase and return the target amount when the bill matures. For instance, if you buy a $100k 1-year Treasury bill, it might cost $96.5k today. - Now you have $3.5k in your pocket and a guarantee that you'll get $100k in a year when the bill matures. Use that $3.5k now to purchase call options or vertical spreads on the S&P 500 index to capture the upside that you can. Your return is limited by the structure of that options trade and what its maximum payoff is.

If you're willing to accept more than 0% downside, then you can achieve a higher potential upside cap as well.