I suppose the only way to find out the details is to call or visit a branch. I would think that if there is a cap, they would mention that fact (similar products at other banks, which have a cap, are generally upfront about the cap). The main risk here is the possibility of "lost opportunity," i.e., the difference between earning something, no matter how small, had the money been invested in a traditional CD, and this CD in the event that it earns nothing in all three years. Judging from my impression of the readers of this website, again I think that most readers will not be interested in this deal. Another downside worth noting is that equity-index CDs often have severe early withdrawal penalties (assuming an early withdrawal is even possible). Opinion about equity-index CDs seems quite varied, from some who think the negatives outweigh the advantages, to others who seem to think that such products have advantages over an index etf/fixed-rate CD combo.