Lehman Cut from A+ to A by S&P

Morgan Stanley, Merrill Lynch & Co. and Lehman Brothers Holdings Inc. plummeted in New York trading after Standard & Poor's lowered credit ratings for the investment banks, saying they may have to book more writedowns on devalued assets.

Morgan Stanley, the second-biggest U.S. securities firm by market value, was cut to A+ from AA-, S&P said today in a report. Merrill Lynch, the third-biggest, was cut to A from A+, as was Lehman Brothers, the fourth-biggest. Goldman Sachs Group Inc., the largest of the group, was affirmed at AA-. The outlook on all four New York-based companies remains negative, S&P said.

The ``actions reflect prospects of continued weakness in the investment banking business and the potential for more write-offs, though not of the magnitude of those of the past few quarters,'' Tanya Azarchs, an S&P analyst, said today in a statement.

The ratings downgrades may make it harder for the banks to sell derivatives such as credit-default swaps that are tied to bonds or loans, said Brad Hintz, an analyst at Sanford C. Bernstein in New York. Single-A rated firms are less desirable as trading counterparties for fixed-income derivatives that extend longer than five years, he said.

The firms are also likely to have to post more collateral on the trades they've already made with other parties, raising their costs, Hintz said.