"The chairman of UBS AG stepped down today after an internal investigation by the Swiss banking giant revealed ""shortcomings in risk management"" in the company's dealings with Long-Term Capital Management L.P., the massive speculative fund that nearly collapsed last week.</br></br>Mathis Cabiallavetta and three top executives were the first casualties in the upper echelons of the bevy of blue-chip financial firms that lent hundreds of millions of dollars to Long-Term Capital -- and then wound up rescuing the fund. But many on Wall Street are bracing for similar shake-ups, particularly amid public scoldings about a lack of lending controls at many institutions by Federal Reserve Chairman Alan Greenspan and Treasury Secretary Robert E. Rubin.</br></br>""There have got to be sacrificial lambs,"" said a senior Wall Street executive. ""We're all waiting to see who is going to take the blame.""</br></br>Executives of some firms speculated that lower-level managers may take the fall, particularly in cases where their own chiefs were unaware of the extent of the risk their companies were taking.</br></br>Indeed, Bank of Italy Governor Antonio Fazio today said he was unaware until this week of the involvement of Italy's Foreign Exchange Office UIC in Long-Term Capital -- even though he chairs UIC, which manages Italy's foreign-exchange reserves on the central bank's behalf."