> Equity valuations in general could simply become so high that the ongoing fund flows required to keep them up at these levels could become insufficient, especially as the Federal Reserve tightens its monetary policy in response to inflation. Upward momentum could turn into downward momentum, causing the marginal investor to shift away to other assets and other markets.

I'd honestly be curious if the Fed would try to shore up fund flows to keep stock prices rising. It sounds like an awful idea, and effectively amounts to a naked "let's make up money and hand it to rich people" play. But is it really that different from bond purchases?