This is all part of a coordinated national rally. The Service Employees International Union organized demonstrations in Chicago as well as in 35 states throughout the country. They are specifically targeting these two companies, Bank of America and AIG, because they are two of the recipients of a combined $218 billion in government bailout money.
Many of the demonstrators say they believe that money could have been better spent. At the same time, they are rallying against these corporate bailouts, they're also complaining about the bonus payments to AIG workers.