Zions Bancorp., the Salt Lake City-based lender with operations in 10 western U.S. states, fell the most in eight years in Nasdaq trading Thursday on concern about the bank's losses from foreclosures.

Zions dropped $4.67, or 15 percent, to $26.95 in trading Thursday before closing at $27.05. The stock has plunged more than 60 percent in the last 12 months.

"Weakness" in residential construction and land values in the Southwest will harm loans and is "expected to persist into 2009," the lender said in a presentation attached to a June regulatory filing.