Ten years after the collapse of Lehman Brothers, and despite Congress’s efforts to protect Mom and Pop with the 2010 Dodd-Frank Act, the small investor is increasingly vulnerable to shoddy practices on Wall Street.

Dodd-Frank was passed to rein in too-big-to-fail banks and establish new protections for consumers and investors. That included marching orders for the Securities and Exchange Commission to look into reforms meant to level the playing field between everyday investors and the sales agents who try to separate them from their money.

In the years since then, instead of enacting more rigorous requirements for the nation’s 629,032 stockbrokers, the agency has proposed a code that isn’t much stricter than the rules we already have. The S.E.C. has also chosen to do nothing with the authority it received with Dodd-Frank to unshackle investors from contracts that prevent them from taking brokers to court when things go off the rails.

The agency’s official actions and failures to act are not the only problem.

Last month, Hester Peirce, an S.E.C. commissioner appointed by President Trump, threw out a bombshell, signaling that she would support requests from companies looking to block shareholders from bringing class-action lawsuits. Ms. Peirce told Politico that public companies “absolutely” should have the option of demanding arbitration instead of allowing class-wide court actions to proceed.