Although U.S. stocks closed lower on Tuesday, there were a few notable insider trades.

When insiders purchase shares, it indicates their confidence in the company's prospects or that they view the stock as a bargain. Either way, this signals an opportunity to go long on the stock. Insider purchases should not be taken as the only indicator for making an investment or trading decision. At best, it can lend conviction to a buying decision.

Westrock Coffee Company, WEST.
Ambrx Biopharma, AMAM.
Frontier Communications Parent FYBR.