The lights have been off at the online brokerage stock party for the past two months. Now the much-anticipated after-party is looking dim, too.

Investors' only hope may be to grab some

Charles Schwab

(SCH)

and hold tight.

After a record quarter of trading numbers, some analysts expect Nasdaq trading volumes -- and thus, trading commissions -- to decline by about 15% this quarter before heading into the summer doldrums. Meanwhile, ballooning margin debt has many observers questioning if investors will react to a down market by borrowing less. That, too, will hit online brokerages' bottom lines because they earn interest on the money they lend investors to buy stocks.

The difference with Schwab, observers say, is that the company earns revenue from many different sources and therefore isn't as reliant on online trading activity as most of its competitors.

Those two factors explain why the stocks of more trading-dependent cyberbrokers such as

Ameritrade

(AMTD) - Get Report

and

E*Trade

(EGRP)

have fared worse than that of

Charles Schwab

(SCH)

. The less a broker depends on

Nasdaq

volume for commission revenue, the less its stock is knocked down by a market decline. While Schwab fell 5% since March 1, Ameritrade and E*Trade gave up 24% and 23%, respectively.

Charles Schwab Outpaces Nasdaq 100
E*Trade, Ameritrade On Decline

Falling into the same camp as Schwab in terms of having both "clicks and bricks" is

TD Waterhouse

(TWE)

, the online unit of Canada's

Toronto-Dominion

(TD) - Get Report

. It's given up less than 1%, but unlike Schwab, the stock hasn't been much of an investment. Its 52-week high is only 27 1/4, compared with Schwab's 67 1/8, and it's now trading below its initial public offering price.

Schwab, which had more than $800 billion in assets at the end of the first quarter, recently bought

U.S. Trust

, a high-end investment services company that adds revenue from businesses such as trust services to Schwab's bottom line.

Also, about one-third of Schwab's assets are managed through its financial advisers, and their clients are unlikely to make wild bets that could cause them to suddenly liquidate their positions.

Then there's Schwab's mutual fund business -- each of the companies that takes part in it pays the broker a fee. During the most recent quarter, that amounted to about 15% of revenue.

And while other online brokers such as E*Trade have plowed a fat percentage of revenue into marketing, thereby erasing profits, the more established Schwab has the financial heft to spend big but still churn out profits.

Here's a look at the declines in stock price among some of those smaller brokerages that are pure online plays.

DLJDirect

(DIR)

, the tracking stock for the online brokerage unit of

Donaldson Lufkin & Jenrette

(DLJ)

, is down 20%.

National Discount Brokers

(NDB)

, the parent company for

ndb.com

, saw its stock nearly double during the first half of March before starting a decline that has it down 35% since March 1. Tiny

Wit Capital

(WITC)

, which runs an investment bank and an online broker, is no exception. Its loss: 35%.

Finally, there's another group of online brokerages that daytraders love but which investors don't because they are so small.

Web Street Securities'

(WEBS)

, for instance, has just $800 million in customer accounts. Web Street's stock is off 26%. Another small player,

JB Oxford

(JBOH)

, is down 35%.

"I think the other online brokers have been financed by the markets and they have not proven yet that their business method is working -- that they're generating a sufficient return on their capital," says Jeff Van Harte, manager of the

Transamerica Premier Equity

fund, which is long Schwab.

Seems that's the party line among investors.