When Zac Posen presents his spring 2011 collection Sept. 11, the lush, swirling thousand-dollar gowns the designer is best known for will be missing. In their stead will be jersey knit pants and other sporty looks. That's because Mr. Posen is showing his Z Spoke by Zac Posen line, a less expensive contemporary label, rather than his main collection, at New York fashion week.

Almost every high-end fashion designer has been forced to cut prices or launch lower-priced collections since the economy tanked....