By Paul Moss
BBC News, Chicago
What happens on the exchange has a wider impact on the local economy
They still do things the traditional way on the floor of the Chicago Exchange.
Computers play a role, but stocks, shares and just about any other financial commodity are still traded by dealers waving their hands in the air and trying to shout louder than the person standing next to them.
It is a hectic place at the best of times, but the past few days have been particularly hectic.
"We're in uncharted waters," says Vic Lespinasse, an old hand on the trading floor.
"We've never seen a situation where there's this tremendous turmoil. There's opportunities to make money and lose money. But it's a lot easier to lose money."
Watching this scrum of dealers and their financial feeding frenzy, it can all seem strangely abstract, nothing to do with those of us who do not invest in stocks, or try to play the financial markets.
Shares are bought and sold in companies far away, while others compete for the option to buy several tonnes of wheat a year after next.
But one of Chicago's leading financial analysts, Monee Fields-White, has a warning to those who might think they are immune from this turmoil.
"It is a troubling time for everyone because everything is connected," she says.
Ms Fields-White cites the near-collapse this week of the American insurance giant, AIG.
"A lot of the securities that AIG insured are within state pension funds. So state and government workers who may be close to retirement have seen $18bn of losses."
She also argues that job losses in the finance sector will have a wider impact.
"We're not just talking about high executives. It's everyone, administrative assistants, mail-room staff," she says.
"Those people spend money, and that loss of spending can then affect other areas of our economy."
Over in the Bucktown area of Chicago, Trisha Tunstall was well aware of that.
She was holding a party at her fashionable boutique, "P45", as a way to try to get new customers in, and keep the old ones interested.
The last few months have seen a serious dip in sales.
"The person that lost their job in the bank? The woman who comes into the store could be their wife, or their daughter.
"I had a customer come in today who hadn't been in for months. She said her husband was keeping her on a tight spending freeze," she says.
Ms Tunstall echoes the fear that troubles in one area of the economy will ripple out elsewhere.
"We employ a lot of people. And if you see a lot of small businesses shutting down, people are losing their jobs."
And they end up at places like the Garfield Centre, in the Westside neighbourhood.
People come here to find out about job vacancies, but also to get help with skills training and other forms of support for the unemployed.
"Customers come in and say 'I just need a job, give me a job today,'" says Aviva Brill-Roblez, the centre's manager.
She was speaking just as figures were released showing that unemployment in the state of Illinois has gone up again.
The credit crunch has played a role here.
"So many companies are being down-sized, so many companies are being out-sourced, it's decreasing opportunity for the everyday person," said Ms Brill-Roblez.
That lack of opportunity is felt acutely by Jocelyn Charles, who has not worked for more than a year.
"You keep saying to yourself, maybe today will be the day that somebody gives me a chance - knowing that you're going to come back home, unemployed, with nothing changing.
"I don't know what else to do. What is the next choice?"
Paul Moss is reporting from Chicago for the World Tonight.
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