JUDY WOODRUFF: World stock and currency markets were rocked for a second straight day today, as China continued to devalue its currency, the yuan.

While the drop is not expected to have a big affect on most Americans, and the tumult on Wall Street had calmed by day's end, some analysts are saying that for U.S. companies who are doing a lot of business inside China, among them Apple, Coca-Cola, and fast food retailer Yum! Brands, the change could hurt sales and trim profits.

For more on China's move and its ripple effects, we turn to Eswar Prasad, professor of trade policy at Cornell University, and Mike McDonough. He's chief global economist at Bloomberg Intelligence.

Welcome to you both.

Eswar Prasad, to you first. What does it say that the Chinese Central Bank for the second day in a row has decided to let its currency be decided by market forces?

ESWAR PRASAD, Cornell University: Well, China is doing exactly what it said it would do, which is to let the currency's value be determined by the market, and the market wants to push the yuan a little lower because China's economy isn't doing so well.

But there is also a good side to it, because China has been trying to open up its capital account, that is, make it easier for money to flow in and out of China. And for good reasons, for diversification and so forth, a lot of money had been going out of China because households and corporations want to invest abroad.

Now, the difficulty is that China is undertaking this move at a time when it's good for China, but not necessarily for the rest of the world. So, the Chinese economy has been weak. The Central Bank has been trying to do everything it can to prop up the economy, through interest rate cuts, reducing the amount of reserves that Chinese banks have to keep with the Central Bank, so that there can be more credit flowing to the economy.

Nothing has worked that well. So, now they're turning to the currency as an added boost. This may be good for China, but it is going to be complicated for the rest of the world.

JUDY WOODRUFF: And, Mike McDonough, are we better able to today to tell whether this is driven by true — a desire for reform, to let these currency rates be determined by market forces, or is it all about boosting China's lagging growth rate?

MIKE MCDONOUGH, Bloomberg: Well, I think Eswar hit the nail on the head, where the timing is perfect.

It's about the reform, but it's also about the devaluation that you saw. Basically, China took a measure that is certainly going to help bolster their export sector, but then they put this caveat on the end saying, going forward, we're going to let the market set the rate.

So, if you were a policy-maker, you got exactly what you want. But the problem is, by doing this sudden devaluation, they did lose a bit of credibility. So there's talk about the yuan being an SDR, the IMF recognizing it as a sort of global currency.

They really hurt their credibility by doing this sudden devaluation, this one-off 2 percent. So, what they need to do now is prove, follow through, continue letting the market set the yuan. And what you're seeing and why you're seeing so much turbulence in the market is because, because they did the 2 percent, they lost the credibility.

People are scared now. People are concerned that if China continues slowing down, they're going to do another one-off devaluation, and that's a big risk. They need to now follow through. There is an execution risk. They need to follow through with what they said.

JUDY WOODRUFF: Eswar, I know that there are implications globally for this, but let's try to focus on the United States right now. We mentioned U.S. companies that are deeply invested in China. Where do they stand to come out of this, or is it just too early to know yet?

ESWAR PRASAD: So far, the depreciation of the yuan has been relatively modest.

And, remember, the U.S. dollar has been very, very strong over the last year. It's appreciated by about 20 percent relative to currencies like the euro and the yen. There is only one major currency against which it is appreciated by this 2 percent before this devaluation, and that's the Chinese yuan.

So this is just adjusting for that a little bit. But for the U.S., it is going to be in a slightly uncomfortable if the yuan and every other major currency is on the other side trying to weaken their currency relative to the dollar.

Now, for companies that are in the U.S., but are operating in China, it's a double blow. First of all, this signals that the Chinese economy is going to remain weak. And the government in China is certainly very concerned about the weakness in the economy, so that's going to affect earnings of a company like Apple in China.

But, in addition, a lot of the foreign earnings in China and elsewhere are going to be affected when that money comes back to the U.S., because the U.S. dollar is stronger and China's move is certainly going to keep the dollar even stronger than it would otherwise be. And that will is going to earnings in dollars, so it could potentially be a double blow for companies like Apple operating in China.

JUDY WOODRUFF: Mike McDonough, what would you add to that? What do you see as the effect in the U.S.?

JUDY WOODRUFF: Go ahead.

MIKE MCDONOUGH: What you really need to look at isn't the devaluation. It was relatively minor.

The problem is, why did they do it? China's economy is hurting. It is slowing down. They're doing everything they can to — in a best-case scenario, in my view, China, they don't have a resurgence in growth. They stabilize growth.

So you have the world's second largest economy, which has been this big tailwind for global growth, not just in the U.S., but everywhere — they're a big consumer of our exports — suddenly sputtering. So this tailwind is becoming a headwind. That's the real concern. It's not the devaluation. It's, why did they do it?

China's economy is slowing. Demand is slowing for goods in general, and that's the real problem. They need to basically buoy growth.

JUDY WOODRUFF: And, Eswar, as you're saying, that has real effects on countries around the globe and including in the U.S., I mean, these companies that we mentioned and others. I think some American consumers may also be asking, is this going to affect me?

ESWAR PRASAD: For the American consumers, it could be a mixed blessing, because if China's currency continues to weaken and if other currencies around the world try to weaken themselves even more in order to compete more effectively with China, that's going to mean a stronger dollar.

And a stronger dollar means a couple of good things for U.S. consumers. Number one, it means cheaper imports from the rest of the world. And, second, it also means lower interest rates, because even if the Fed were to hike short-term policy interest rates sometimes later this year, long-term rates in the U.S. are likely to remain low.

And long-term rates are what determine mortgage rates, auto loan rates and so on. So that's all good for U.S. consumers. But there are some sectors of the economy that are very export-oriented that are going to get hurt, because, first of all, foreign companies are going to be much more competitive here and Americans are going to find it much harder to export to the rest of the world.

So the benefits are going to be widespread, but the pain is going to be concentrated in some sectors that could face fairly significant job losses and the loss of economic momentum.

JUDY WOODRUFF: Mike McDonough, just quickly, so, what do you suspect now? What are you looking for now as we watch what China is doing?

MIKE MCDONOUGH: You know, I think, you know, China is going to have to continue implementing a bit more stimulus. I think they have the firepower to at least stabilize growth that you have seen in China, but I think you're not going to see the China of the past.

China is going to continue to slow. They're going to try to stabilize that slowdown. They're going to continue trying to reform their economy. And they're going to continue opening up, but it is going to be these basically short cycles where everyone gets really euphoric about China because they think things are looking better, and then they're going to implement some reforms, there will be some signs that things are sputtering again, and then there will be these concerns about the hard landing.

Right now, we're in one of these down periods, but eventually things will stabilize. But it's going to, going forward, be this panic and euphoria very short period phases going on in China.

JUDY WOODRUFF: They have certainly gotten everybody's attention for the last two days.

MIKE MCDONOUGH: Definitely.

JUDY WOODRUFF: Mike McDonough with Bloomberg, Eswar Prasad at Cornell University, we thank you both.

MIKE MCDONOUGH: Thank you.

ESWAR PRASAD: Thank you.

MIKE MCDONOUGH: Thank you very much.