'Shark Tank' star Kevin O'Leary says cracks are forming at regional banks amid high interest rates, and the US should guarantee payroll accounts to keep small businesses safe

• The banking sector is starting to crack amid higher interest rates, Kevin O'Leary warned.
• The "Shark Tank" investor pointed to banking stress stemming from commercial real estate debt.
• That's why the US needs to extend deposit insurance up to $100 million for payroll accounts, he said.

There's a storm brewing in commercial real estate, and that could mean more turmoil for the banking system, which is saddled with most of the debt in that sector, "Shark Tank" star Kevin O'Leary warned.