Robert Shiller

list of bellwether stocks Goldman Sachs, Morgan Stanley, Freeport McMoran, Monsanto and Mosaic

Worst Year Ever for Stocks:

TARP: Troubled Asset Relief Program. This is the Treasury's big $700 billion ($850B including pork) program that has been used to prop up financial institutions.
TAF: Term Auction Facility (or TAFfy). Program by which the Fed auctions funds to financial institutions — allowing them to use their toxic assets for collateral.
TALF: Term Asset-Backed Lending Facility (or "son of Taffy"). Recently announced Fed program designed to help the market for student, auto and other consumer loans.
CPFF: Commercial Paper Funding Facility. Buys commercial paper directly from corporations.
AMLF: Asset-Backed Money Fund Lending Facility. Fed program designed to buy short-term paper (including commercial paper) to prevent money market funds from "breaking the buck."
TSLF: Term Securities Lending Facility. Fed program that lets banks swap bad mortgage and other debt from their books in exchange for Treasuries.
SLF: Special Lending Facilities. Originally designed to loan money to fund JPMorgan's purchase of Bear Stearns in March. Also used to back AIG's balance sheet to avoid total collapse.
PDCF: Primary Dealer Credit Facility. This is the Fed program that allowed broker/dealers and other non-banks to tap the Fed's discount window (back when there were independent broker/dealers)

102 were trading under $10
41 were trading under $5
204 were trading with a market cap of less than $4 billion

These are not the only criteria used for inclusion in the index, but S&P 500 companies typically have market caps above $4 billion and stock prices above $5. Furthermore, many institutional fund managers are prohibited from owning stocks that trade below $10 or $5, depending on the firm.

In other words, a lot of companies currently in the S&P 500 may not be eligible for membership or, more importantly, ownership by major institutions. That, in turns, may mean more selling ahead, even though stocks are "cheap" based on a variety of metrics. For example, 163 stocks in the S&P 500 are trading below book value, or assets minus liabilities, including non-financials like Alcoa and Duke Energy.