nice to have you on the program. >> thank you, susie. >> susie: let me begin by just asking you what are the risks of all these events, that spanish bailout, the debt crisis in greece, the falling euro. what's the intact and the risk of all of that to american businesses and our economy? >> susie, we went into the weekend knowing that europe had a debt issue and europe had a growth issue. we come out of the weekend with the news that europe may also have a banking system issue. the minute you bring in the banking system it's like an amplifier, something that we discovered in this country a couple of years ago. banks have a way of amplifying shocks in the system because banks are like the oil in your car. they link up so many different parts. and the problem for the u.s. is that not only is it going to have to cope with a growth issue out of europe. europe is an important export market. we sell a lot to europe. europe is going to grow less. now the strains in the banking system. and the minute you introduce strains into the banking system there's always a fear that governments will be

>> susie: a big t.g.i.f. on wall street. the dow closed higher by triple digits today just a day after posting its biggest drop in more than a year. >> tom: there may be some relief now that a new rulebook for fixing the nation's financial system is closer to becoming a reality. you're watching nightly business report for friday, may 21. this is "nightly business report" with susie gharib and tom hudson. "nightly business report" is made possible by: this program is made possible by contributions to your pbs station from viewers like you. thank you. captioning sponsored by wpbt >> susie: good evening, everyone. investors cautiously tip-toed back to the stock market today, after yesterday's massive sell off. tom, all the major averages closed up, but there was still a wave of heavy selling at the open. >> tom: susie, it was a choppy day and at the start of trading. the dow fell below the psychologically important 10,000 level. but it stayed above its flash crash low. by late morning, buyers came back and it finished higher by

joining us now, art hogan, chief market strategist at jeffries & co. >> hi, susie. >> susie: art, if this debt crisis in europe spreads to other countries beyond greece,ç what will happen with the u.s. stock market. >> susie, one of the biggest things that has happened today and has been a consistent pattern, the more we're concerned with what is going on with the sovereign debt situation and all of greece, in particular, the euro sells off, and that's going to continue to be the case, as we're concerned with how much debt other european nations, and when that happens, the dollar goes up, as tom alluded to in the opening. but that has an effect on commodities. understanding that all commodities are dollar-based, we saw it sell off specifically. and that's a big part of the s&p 500. that's part of the story. the dollar strengthening makes commodities go down. if it is 25% of the s&p 500 that is represented by the commodities, you'll see thqá be a natural drag. and another story that hasn't gotten much attention is the china demand story. and the china demand story has come back into

i'm susie gharib. goodnight everyone and goodnight to you too, tom. >> tom: good night, susie. i'm tom hudson. goodnight everyone, we hope to see all of you again tomorrow night. "nightly business report" is made possible by: this program was made possible by contributions to your pbs station from viewers like you. thank you. captioning sponsored by wpbt captioned by media access group at wgbh access.wgbh.org >> more information about investing is available in "nightly business report's" video "how wall street works". to order this dvd, call 1-800- play-pbs or visit online at shoppbs.org. >> be more.

but first to susie gharib, anchor of the "nightly business report" here on pbs. she joins us from the new york stock exchange. susie gharib, first of all, it's being reported there may have been human error involved in that plunge today. what have you learned about it? >> well, it may have been human error, judy, and that may have been compounded by some electronic trading. here's what we know so far. there were two events and we don't know which came first and if they were connected. one thing was that around 2:30 today, mysteriously, shares of procter & gamble and 3m suddenly plunged. and that triggered some electronic trading. also today, a trader accidentally placed an order for $16 billion instead of $16 million of what's called e-minis these contracts traded on the chicago mercantile exchange. we don't know which came first and if they're connected. our sources are telling us the trader was working for citi. citigroup has not confirmed that yet. but that was part of what was going on. you know, i want to say you just did your greece report. before this free

for that, we're joined again by susie gharib, anchor of pbs's "nightly business report". susie, thanks for joining us again. what-- what more is known today about what happened yesterday? >> you know, it's hard to believe but they're still trying to figure out what happened. it turns out that decoding what happened yesterday is not so easy. there are very complex systems at work here. officials here at the new york stock exchange as well as the nasdaq and regulators are investigating. here's what we know tonight. at first it was thought it was human error. now turns out that is too simple an explanation. the focus now is on computerized trading. it appears that some dramatic moves in the currency markets yesterday may have triggered computerized program selling in the stock markets. and once that happened, the stock transactions were like a domino effect. anything that was available to sell was sold. also today a lot of fingerpointing going on between the new york stock exchange and the nasdaq, the blaming who was really at fault here. the chicago mercantile exchange said