But the pendulum may be swinging back toward the tenant, even though most new construction is being pre-leased. "I'm seeing people pulling back left and right, getting very conservative and trying to minimize the time on their lease," said Jeff Liljeberg, senior vice president for CB Richard Ellis.

In 2000, downtown demand was greatest for Class A properties, which had a vacancy rate of just 5.6%, and properties in River North, where the vacancy rate in the area just north of the Loop was a tight 6.6%. The West Loop was just as hot, with a vacancy rate of 6.7%, according to the CB Richard Ellis study. Examples of just how tight the market is in those areas were Dearborn Plaza at 20 W. Kinzie in River North and 550 W. Washington Blvd. Just west of the Loop. Those buildings opened 98% leased, according to CB Richard Ellis. Both properties are close to public transportation, high on the wish list of companies aiming to attract and keep employees.

Liljeberg said it wasn't uncommon recently to see several prospects vying for top spaces, which for the winner means paying rents ranging from $21 per sf to $32 per sf for Class A properties. Although some once white-hot dot-com companies ended the year with a whimper, if not out of business, any slack in demand was being picked up by law firms, financial service companies as well as the telecommunications industry.