them, not the client, the most money. >> this proposed rule is the most important thing. >> reporter: tom perez, the secretary of labor, calls the best interest standard crucial. >> that adviser needs to put putt your best interest ahead of their self-interest. >> reporter: but most of wall street and the insurance industry is pushing back hard with an ad campaign saying the rule will raise retirement costs for small businesses. >> they'll make it much harder for my employees to get information on our 401(k). >> reporter: the industry complains the new rule is not simple. as written, it's 34 pages long. peter schneider is the president of insurance giant primerica. >> we all agree we must act in a client's best interest. but it's so complex, so onerous, so costly, it's unworkable. >> reporter: with retirement accounts now a $12 trillion industry, wall street is fighting to keep the fee system that pays its brokers billions. but, maurice, the white house