IndyMac Bancorp (NYSE-IMB) became the latest mortgage casualty in the United States this month, officially triggering the first attempted run on a U.S. bank since the 1970s.

On Monday, U.S. bank stocks suffered their worst single day of performance in years, dropping 8.5%. Some banks, including Washington Mutual (NYSE-WM), tanked 35% on the session.

From their highs last year, U.S. bank stocks now trade a hefty 57% off their best levels. Surging losses, a blizzard of rights offerings, dividend cuts, layoffs and now, growing fears of outright bank failures has exacerbated a panic sell-off this summer.

IndyMac’s collapse marks the first time since the advent of the subprime mortgage crisis a year ago that a U.S. mortgage thrift has failed. Last September, Britain’s Northern Rock plc, a midsized mortgage lender, collapsed and was eventually rescued by The Bank of England. Throughout September, newspapers worldwide portrayed images of Northern Rock customers scrambling to access their funds – eerily reminiscent of Depression era breadlines.

On July 14, IndyMac, the nation’s 10th largest mortgage lender, borrowed a page from Northern Rock as major financial newspapers depicted crowds waiting to access their funds.

IndyMac reopened its doors under federal supervision yesterday. Homeowners were promised a lifeline from impending foreclosures and the FDIC stepped in to protect funds up to $100,000. However, only $1 billion dollars of IndyMac’s roughly $19 billion in deposits was uninsured, affecting about 10,000 customers. But the FDIC has stated it would seek to return up to 50% of uninsured customer deposits.

If you continue to hold the bulk of your savings and liquidity at a U.S. bank – including the largest money-center banks, I strongly suggest moving those assets to TD Ameritrade to purchase Treasury bills or exchange traded funds that invest in short-term Treasury securities like SHV or SHY. Also, other discount or full-service brokers are adequate; just make sure to invest your funds in Treasury designated securities.

Also, consider mutual funds that offer “Treasury” or Government Securities” money-market funds. These products, offered by low-cost Vanguard Group among others, are safe, liquid and maintain a high degree of credibility since assets are 100% invested in short-term government paper.

The only cash sitting in a bank today should be to pay ongoing expenses, bills, etc. Don’t keep the bulk of your precious savings or liquidity stashed in a bank.

Until financial markets stabilize, head for the relative safety of government designated securities and products. These are uncertain times. Act now.