Wall Street’s main regulator is weighing whether to require more transparency of short-selling and the opaque network of stock lending and borrowing that facilitates it, according to people familiar with the matter.

The Securities and Exchange Commission was ordered 11 years ago to impose such rules but never did it. Now, dealing with the fallout from frenetic trading in GameStop shares, the agency under new leadership is considering using its authority to shine more light on the mechanics of the bearish trades.