The Members Exchange just received approval from the US Securities and Exchange Commission to operate as a national securities exchange.As a result, the startup exchange said it's on track to go live during the third quarter of 2020. MEMX is backed back some of the biggest firms are on Wall Street, including JPMorgan, Goldman Sachs, and Charles Schwab. Click here for more BI Prime stories.An upstart stock exchange backed by some of Wall Street's biggest names just got approval from the industry's top regulator.The Members Exchange, a startup exchange backed by JPMorgan, Goldman Sachs, Morgan Stanley, and Charles Schwab, among others, said on Tuesday it received approval from the US Securities and Exchange Commission to operate as a national securities exchange.MEMX's approval comes less than