Austin Lieberman is bearish on the broader market, anticipating a 15% to 20% pullback in SPY and QQQ due to high blended P/E ratios and rising AI-related capex for companies like META and GOOGL. To capitalize on this short-term outlook, he has opened a large position in SQQQ, which currently makes up 43.29% of his shared portfolio alongside a 13.08% holding in AMZN. Technical data for SPY shows it trading at a P/E of 25, significantly above its historical norm of 18-19.