SEC Proposes Rules That Would Squeeze Stock-Market Middlemen

WASHINGTON—The Securities and Exchange Commission voted Wednesday to advance the biggest changes to U.S. stock-market rules since the mid-2000s, aiming to give small investors better prices on their trades and reduce some advantages enjoyed by high-speed trading firms.

Democratic commissioners, who hold three of the SEC’s five seats, supported moving forward on each of the four proposals. Republican commissioners voiced objection to two of the measures. Voting to advance the rules opens them to public comment until at least March 31 before the agency can decide whether to finalize them.