Yep interesting times. Valuation models at these levels depend on EPS growth where buybacks reduce number of shares = more earnings per share. The side effect is a ballooning balance sheet. Can that go on indefinitely? Are upper management (typically near retirement age) at all concerned with the long term effects?

Passive investment and Fed also plays part. Joe 401k and systemic index tracking leads to no public awareness of companies financial health. Buy no matter what the largest cap stocks in proportion to size. Fed is completely aware of all this. Interest rates must never rise otherwise everything seizes. December’s reaction was just that.