Goldman Sachs to buy Innovator Capital for $2 billion

• They limit downside risk and cap profit potential, with some using them as a fixed income alternative.

Behind the scenes: Bryon Lake, Goldman's co-head of third party wealth, years ago worked with Innovator's cofounders when they all were at PowerShares (later acquired by Invesco).

The bottom line: Innovator's 'buffer' has done better on the downside than the upside this year, with the strategy working during the Liberation Day tumult in April but underperforming the S&P 500 since May.