“There are recent developments that concern a few banks that I’m monitoring very carefully,” Yellen told lawmakers during a committee hearing. The FDIC seized control of the bank’s assets, an unusual move suggesting that immediate action was necessary. Yellen told Congress that she was keeping a close eye on the bank’s financial crunch shortly before the California Department of Financial Protection and Innovation announced it had taken possession of the institution Friday morning. Treasury Secretary Janet Yellen and other policymakers are on alert that problems at the institution - which had $209 billion in assets and counted more than half of Silicon Valley-backed startups and health-care businesses among its depositors - could spread.