The S&P 500's gains this year are thanks to just 8 stocks, signaling the banking turmoil isn't over yet, Jim Bianco says

• The S&P 500's gain this year is thanks to only eight mega-cap stocks, Jim Bianco said.
• The Bianco Research boss noted Big Tech companies like Apple and Alphabet have led the index higher.
• Bianco warned banking turmoil might not be over given the broad weakness in the S&P 500.

The S&P 500's year-to-date gains have been driven by just eight stocks, while the other 492 stocks in the benchmark index have fallen as a group in 2023, signaling the banking turmoil isn't over yet, Jim Bianco said.