* Inter-bank lending rate spike fuels credit worry
* U.S. extends $85 billion loan for 79.9 pct stake in AIG
* Morgan Stanley, Goldman Sachs tumble
* Dow off 1.3 pct, S&P 500 off 1.4 pct, Nasdaq off 1.2 pct (Updates to early morning)
By Ellis Mnyandu
NEW YORK, Sept 17 (Reuters) - U.S. stocks slid on Wednesday as a spike in inter-bank lending rates added to fears of credit constraints in the global financial system.
Additionally, investors worried the U.S. government rescue of embattled insurer American International Group <AIG.N> wouldn't be enough to stem turmoil that has rocked markets.
With AIG now in government hands, investors started worrying again about who might be the next in the financial sector to come under strain, sending the S&P financial index <.GSPF> down 3.4 percent.
Shares of Morgan Stanley <MS.N> slumped more than 14 percent to $24.49 on the New York Stock Exchange after CNBC television reported that the U.S. investment bank is weighing whether it should remain independent or merge with a bank. For details, see [
]Shares of Goldman Sachs <GS.N> dropped 9.4 percent to $120 after several brokerages cut their profit outlooks for the investment bank. Credit constraints could hamper business and consumer lending.
"The credit crunch and credit contraction is intensifying," said Peter Boockvar, equity strategist at Miller Tabak & Co in New York. "The action in Morgan Stanley in light of what was better than expected numbers last night is disconcerting."
The Dow Jones industrial average <
> fell 139.72 points, or 1.26 percent, to 10,919.30. The Standard & Poor's 500 Index <.SPX> dropped 16.44 points, or 1.35 percent, to 1,197.15. The Nasdaq Composite Index < > declined 26.25 points, or 1.19 percent, to 2,181.65.The bank-to-bank cost of borrowing overnight dollars fell more than a percentage point on Wednesday, but the premium paid for the greenback and sterling over three months swelled, showing persistent money market strain.
The drop in Morgan Stanley shares came despite the bank's posting quarterly results after the bell on Tuesday that beat Wall Street estimates.
Shares of General Electric were down 7.3 percent at $23.22 and were a top drag on the S&P 500. Boeing <BA.N> weighed on the Dow, with a drop of 4 percent to $59.34 after UBS cut its price target on the plane maker's stock.
Shares of iPhone and iPod maker Apple Inc <AAPL.O> dropped 2.6 percent to $136.30, making the stock a top drag on the Nasdaq.
The government agreed on Tuesday to rescue AIG via an emergency $85 billion loan. AIG shares were off 41 percent at $2.26 on the NYSE.
Banks frantically seeking dollar funds have been stonewalled by others increasingly reluctant to lend amid uncertainty and nervousness following the collapse of Lehman. (Editing by Kenneth Barry)