Thomas Properties did not respond Monday to repeated requests for comment.
The suit filed in Philadelphia Common Pleas Court accuses Thomas and its agents of conveying "false impressions" about sales numbers, starting in 2005, often citing "presale" figures of 60 percent to 70 percent of the 302-unit Murano.
The defendants knew these impressions "would have - and did have - an impact" on unit prices as well as the demand for them, "including prices actually paid by the plaintiffs," the suit contends.
The value of units in condo buildings partly depends on the total sales. Sales numbers also determine the willingness of banks to lend money to purchase those units.
In June 2009, when Thomas hired Accelerated Marketing of Boston to auction 40 Murano units, the developer had sold just 112 and had 12 others under agreement - a total 41 percent.
A total of 178 units hadn't moved since the building opened in mid-2008, just as the real estate downturn was taking hold. The auction was designed to accelerate sales in a Center City market swimming in about 2,000 unsold new condo units.
The 40 auctioned units were sold at prices more in line with the realities of the current market, which has experienced a 7 percent decline in single-family home values since the boom ended in August 2007.
A comparison of per-square-foot prices of units that closed in mid-2010 and those that closed in 2008 shows reductions of about $100 per square foot in some, but not all cases.
Depending on location, condo prices in Center City range from $300 to $700, with Rittenhouse Square commanding the highest, said Realtor/developer Allan Domb of Allan Domb Real Estate.
