Jason Child

5:00PM Groupon — Chicago’s golden-boy tech startup whose founders became billionaires when it went public — tripped over its own feet again Friday. The company, based in the old Montgomery Ward catalog warehouse at 600 W. Chicago, surprised Wall Street after the close on Friday when it disclosed in a regulatory filing that it’s having trouble with its financial controls. It also lowered its fourth-quarter earnings statement — the first results it had reported as a public company. Groupon’s auditor flagged the online coupon site for failing to set aside enough money for customer refunds. Groupon has started offering