A crypto company backed by Coinbase Global is trying to go public in an offering that could be worth billions. But the Securities and Exchange Commission has signalled unease about the company’s core product, a stablecoin, and raised other concerns, according to documents obtained by Financial News sister title Barron’s.

The documents relate to Circle Internet Financial, the company that issues USDC, a stablecoin worth $32bn. Coinbase owns at least a 3.5% stake in Circle, which it valued at $51m last year. Coinbase also shares in the interest income thrown off by USDC’s reserves, and CFO Alesia Haas recently told investors that she’s a big fan of the business, telling analysts, “I should say why I love USDC.“