Maybe it's the bear market. Maybe it's the weight of all those government investigations into Wall Street's business practices. Or maybe it's simply a case of Wall Street analysts getting some religion, after nearly drowning themselves in bull market Kool-Aid.

But it seems more and more analysts -- even ones who toil at firms that do lots of investment banking work -- are willing to tell investors to sell a stock.

Four major Wall Street brokerages currently have sell recommendations on at least a fifth of the stocks their analysts cover, according to new information that U.S. securities firms had to make public beginning this week.

The firm with the most sell recommendations is

Lehman Brothers

(LEH)

, where analysts rate 28% of the 1,435 stocks they cover as ones to dump.

And in a potential sign of increasing analyst independence, 36% of those sell ratings were slapped onto stocks of companies that are investment banking clients of Lehman.

Other securities firms with a bevy of bearish analysts are

Bear Stearns

(BSC)

Citigroup's

(C) - Get Report

Salomon Smith Barney and

Morgan Stanley

(MWD)

. A fifth investment firm,

Credit Suisse First Boston

, has sell ratings on 19% of the 1,177 stocks it covers.

Of course, Wall Street wouldn't be Wall Street if you couldn't also find a few brokerages with a horde of analysts who never saw stock they didn't love.

Three of the Street's biggest bulls are

Goldman Sachs

(GS) - Get Report

,

J.P. Morgan Chase

(JPM) - Get Report

and

UBS Warburg

, each of which has buy ratings on more than 50% of the stocks its analysts cover.

Beginning this week, it became a lot easier for all investors to find out just where the bulls and bear reside on Wall Street. In compliance with a new

Securities and Exchange Commission

regulation, every U.S. brokerage must now disclose the percentage of stocks its analysts rate buy, hold or sell -- or its three-tiered ratings equivalent.

The ratings can be found at the end of every analyst research report. The disclosure also includes information about the relationship between analyst ratings and the investment banking work a firm does.

The new rule is a response to Main Street's growing uproar during the past year over the high number of analysts who continued to tout stocks as good investments, even after the bear market began eating away at investors' portfolios.

The rule embraces some of the provisions of

Merrill Lynch's

(MER)

$100 million settlement with New York Attorney General Eliot Spitzer, who launched a high-profile investigation into analyst conflicts of interest at the nation's biggest brokerage.

The Spitzer investigation, which revealed that some Merrill analysts privately were trashing stocks that they publicly touted, has left a deep scar on the firm's reputation. But even after being publicly humiliated by Spitzer, many Merrill analysts are apparently still running with the bulls.

Merrill reports that its analysts have buy ratings on 49% of the 2,830 stocks they cover. And more than half of those buy ratings are on the stocks of Merrill's investment banking clients.

Meanwhile, Merrill ranks just 6% of the stocks its analyst cover as ones to sell.

But Merrill still has plenty of company when it comes to Wall Street firms failing to muster the courage to tell investors to sell a stock. Other firms with the fewest percentage of analyst sell ratings are Goldman, J.P. Morgan Chase, UBS Warburg and the Prudential Securities unit of

Prudential Financial

(PRU) - Get Report

.

Ironically, Prudential, which doesn't do any investment banking work, is the near the bottom when it comes to telling investors to sell. The firm, which tried to make a name for itself by promoting analysts such as Michael Mayo --who slapped a sell rating on Citigroup last week -- rates just 2% of the 500 stocks it covers as ones to sell.