金融"黑天鹅"是如何推动市场下跌的?

JUDY WOODRUFF: A sell-off hit the financial markets today over worries about Chinese real estate and U.S. Federal Reserve policy. The Dow Jones industrial average gave up 614 points to close at 33, 970. The loss of 1.8 percent was the worst since July. The Nasdaq fell 330 points. That's more than 2 percent. The S&P 500 lost 75 points, or 1.7 percent. For both the Nasdaq and the S&P, those were the biggest percentage drops since May. We're joined now by Diane Swonk of Grant Thornton to help explain what was driving this. So, Diane, tell us, what was behind it?

DIANE SWONK, Grant Thornton: Well, it's really a reality check. What we saw is that the markets had gotten very complacent about the risks out there. What we call black swans, rare events, are now the norm, everything from China slowing. And what happens in China, especially in the real estate markets, can wash up on our own shores. We know that already too many ways. The second largest economy in the world slowing has an effect on the global economy. The Federal Reserve talking about reducing their asset purchases, taking their foot off the gas a bit, no longer providing quite as much support for the economy and for financial markets, and the shenanigans we're seeing in Washington over the lifting of the debt ceiling. Remember, we had a failure to lift the debt ceiling in 2011, which triggered a downgrade in our actual debt status. And the Federal Reserve had to intervene and say that Treasury bonds were still investment-grade when that happened. So, all of this together and the fact that this is the time of year when people come back, and they actually start looking at financial markets and figuring out what's going on, the world has now got a little more black swans out there flocking, instead of just a rare event.

JUDY WOODRUFF: Good to hear the comparison. But, Diane, I see some analysts are saying today this shouldn't have been a total surprise, that it was due in some way?

DIANE SWONK: Absolutely. I mean, we have known about this for over a month now. And the payment by this one fund in China is due on Thursday. And the question is, what will the Chinese government do it -- do in terms of restructuring it, so that it doesn't become a more contagious event, which we have already dealt with from China? But I think the larger issue is, you have also got the Delta variant out there, which has been a game-changer. Here we are going into the fall with the same kind of number of cases we had in January. That is disturbing as well. We know that fatalities lag cases, and they're now picking up. All of this together, I think, has come to sort of focus the financial markets. At the same time the Federal Reserve is meeting and looking a little more hawkish with an economy that might be hotter in terms of inflation, but cooler in terms of growth. And that's not a combination anyone wants.

JUDY WOODRUFF: Well, we are all trying to understand it. And we thank you for giving us this smart look. Diane Swonk, thank you very much.