** Regional lender Western Alliance Bancorp's WAL.N shares fall 5.9% to $77.10

** WAL on Monday filed its latest 10-Q, disclosing the emergence of a $99 million non-performing loan tied to a life-science laboratory/office building

** Bank has ordered an appraisal and will conduct a valuation analysis to determine any financial impact

** "The latest disclosure is disappointing on the eve of its Investor Day and we expect WAL to get some tough questions around its larger credit exposures and optically lower ACL (allowance for credit losses) as a result" - Piper Sandler analyst Matthew Clark

** As of last close, WAL stock down 2.6% YTD