The

Dow Jones Industrial Average

breached 10,000 for the first time today, but couldn't hold its gains and ended the session slightly lower.

The Dow closed down 28.03, or 0.3%, to 9930.74. The Dow broke through the 10,000 mark for the first time ever at 9:50 a.m. EST. The Dow traded as high as 10,001.79, up 43.02, before fading.

The

S&P 500

slipped 0.87, or 0.1%, to 1306.39.

The Nasdaq Comp gained 7.79, or 0.3%, to 2439.23. Meanwhile, the

Philadelphia Stock Exchange Semiconductor Index

skyrocketed 4.5%.

The

Russell 2000

slumped 1.68, or 0.4%, to 399.16.

TheStreet.com Internet Sector

fell fractionally to close at 604.65.

TheStreet.com E-Commerce Index

gave up 0.30, or 0.3%, to 109.89.

The 30-year Treasury bond was up 23/32, to 96 24/32, yielding 5.473%.

Brokerage stocks rallied while bank stocks tumbled. The

American Stock Exchange Broker/Dealer Index

jumped 3%, while the

Philadelphia Stock Exchange/KBW Bank Index

fell 2%.

In financial services news,

Citigroup's

(C) - Get Report

board approved a $2 billion stock buyback today. Citigroup fell 1 1/4 to 64 11/16.

On the down side, oil service stocks fell. The

Philadelphia Stock Exchange Oil Service Index

tumbled 2%.

On the

New York Stock Exchange

decliners beat advancers 1,664 to 1,299 on 745 million shares. On the Nasdaq, losers beat winners 2,278 to 1,703 on 976 million shares.

On the NYSE, 75 issues set new 52-week lows while 58 touched new highs. On the Nasdaq, 113 issues set new lows while new highs totaled 74.

Most active on the Big Board was

Compaq

(AOL)

, with 22.4 million shares changing hands. It was up 1 to 32 3/8.

On the Nasdaq,

Dell

(DELL) - Get Report

was most active, with 29.5 million shares changing hands. It was up 11/16 to 44 3/8.

Market data above are preliminary. Updated numbers and analysis will follow in the Market Roundup

3:05 p.m.: Stocks Turn Slightly Mixed

The major market averages were mixed going into the final hour of trading, with the

Nasdaq Composite Index

leading on the plus side.

The Nasdaq comp was up 10 to 2442.

The

Dow Jones Industrial Average

was down 11 to 9948. The Dow breached the 10,000 level

for the first time ever today before it eased off the milestone.

The

S&P 500

was up fractionally at 1307. The Russell 2000 was down 1 to 400.

Internet stocks were higher.

TheStreet.com Internet Sector

index was up 3 to 607.

TheStreet.com E-Commerce Index

was up 1 to 111.

The 30-year bond was up 23/32 to 96 24/32, yielding 5.47%.

In the news, in an interview with

Reuters

,

Goldman Sachs

superstrategist

Abby Joseph Cohen

said current stock prices were justified in light of the strength in the U.S. economy. Cohen was quoted by

Reuters

as saying: "The bull market is not over."

Elsewhere, the

Philadelphia Stock Exchange Semiconductor Index

was up 5%.

Morgan Stanley Dean Witter

raised its rating on several semiconductor equipment makers today, helping bolster the sector.

On the

New York Stock Exchange

, decliners were beating advancers 1,658 to 1,232 on 561 million shares. On the Nasdaq, losers were beating winners 2,195 to 1,624 on 746 million shares.

On the NYSE, 64 issues had set new 52-week lows while 51 had touched new highs. On the Nasdaq, 96 stocks had set new lows while 69 touched new highs.

Most active on the Big Board was

Compaq

(AOL)

, with 18 million shares changing hands. It was up 1 9/16 to 32 15/16.

On the Nasdaq,

eFax.com

(EFAX) - Get Report

was most active, with 19 million shares changing hands. It was up 7 3/8, or 34%, to 29 on yesterday's news it will provide free fax-to-email service to

Xoom.com

(XMCM)

. For its part, Xoom.com, which announced a secondary offering of 4 million shares, was off 5, or 7%, to 65.

Focus: Nissan Receives Proposal from Renault

Troubled Japanese automaker

Nissan

(NSANY)

said it received a proposal from French automaker

Renault

today, which includes Renault's possible equity participation in Nissan.

Yoshikazu Hanawa, Nissan president and chief executive, in a statement released by

Nissan North America

on behalf of its parent, said Nissan has "decided to negotiate exclusively with the French motor company. We will work out conditions for forming an alliance in the days ahead so that a conclusion can be reached by the end of this month."

Also, Renault's offer includes a possible equity stake in

Nissan Diesel

, the statement said.

Nissan was up 3/16 to 7 11/16.

1:52 p.m.: Most Major Indices Tumble Back Into the Red

Stocks were slightly weaker on this historic day, as only one major market index was on the plus side at midafternoon.

The

Dow Jones Industrial Average

hit 10,000 and inched past it by a hair for the first time ever today, but quickly after it hit that level it backed off.

The Dow traded as high as 10,001.79, up 43.02, before coming off those highs and slipping back below five figures. The Dow was down 14 to 9945.

Meanwhile, the

Nasdaq Composite Index

was the lone barometer in the green, up 6 to 2438.

The

S&P 500

was down 1 to 1306. The

Russell 2000

was down 2 to 399.

TheStreet.com Internet Sector

was down 2 to 603.

TheStreet.com E-Commerce Index

was up 1 to 111.

The 30-year Treasury bond was up 22/32 to 96 23/32, yielding 5.47%.

On the

New York Stock Exchange

, decliners were beating advancers 1,643 to 1,197 on 473 million shares. On the

Nasdaq Stock Market

, losers were beating winners 2,159 to 1,556 on 632 million shares.

On the NYSE, 58 issues had set new 52-week lows while 47 had touched new highs. On the Nasdaq, 82 issues had set new lows while new highs totaled 63.

Most active on the Big Board was

Compaq

(AOL)

, with 15 million shares changing hands. It was up 1 1/2 to 32 7/8.

On the Nasdaq,

eFax.com

(EFAX) - Get Report

was most active, with 18 million shares changing hands. It was up 8, or 37%, to 29 9/16 on yesterday's news it will provide free fax-to-email service to

Xoom.com

(XMCM)

. For its part, Xoom.com, which announced a secondary offering of 4 million shares, was off 3 5/8, or 5%, to 66 1/2.

12:58 p.m.: Midday Musings: Dow Treads Water as Buyers Focus on Tech

12:01 p.m.: Dow Struggles Back Into Positive Territory

Having seen the confetti and what-not people tossed around at the

New York Stock Exchange

, you might be wondering if there were similar fetes on trading floors. More cheering, maybe?

"No, we didn't cheer, but we did watch the silliness on the floor," said Doug Myers, vice president of equity trading at

Interstate/Johnson Lane

.

And then there's this from a tech trader:

"Yeah right, oh please. Listen, I've got to hop."

Anyhow, after everybody and his uncle sold index futures as soon as the

Dow Jones Industrial Average

crossed 10,000, knocking stocks lower, the market's managed to clamber back into positive territory. The Dow was lately up 1 to 9959, while the

S&P 500

was up fractionally at 1308. And despite what short-term resistance there is at the milestone, the tone of the market is good.

"Money continues to flow where investors think they're going to get their best return," said Myers. "Right now, that continues to be the stock market."

Tech Focus

Tech stocks are outperforming the rest of the market today, and no wonder. Most of them trade on the

Nasdaq Stock Market

. Since none of these four-letter stocks are in the Dow, investors are having an easier time bidding them higher. The top three in the

Nasdaq 100

--

Microsoft

(MSFT) - Get Report

,

Intel

(INTC) - Get Report

and

Cisco

(CSCO) - Get Report

-- were some of the best performers. Obviously, there's been some buying in the Nasdaq 100 futures.

The Nasdaq 100 cash index was up 13 to 2073, while the

Nasdaq Composite

was up 14 to 2445.

TheStreet.com Internet Sector Index

was up 2 to 607.

10:59 a.m.: Dow Slips Into the Red After Breaking Through 10,000 Level

The

Dow Jones Industrial Average's

first embrace of 10,000 proved just a fleeting flirtation, as the blue-chip index (along with much of the rest of the market) quickly retreated into the red.

The Dow lately was down 4 to 9955, having peaked at 10,001.79 around 9:50 a.m. EST. Strength in

Union Carbide

(UK)

and

Merck

(MRK) - Get Report

helped to power the milestone-cracking move, but those stocks were off their best levels and most Dow components were down. The

S&P 500

was down 1 to 1306.

The tech-spiced

Nasdaq Composite Index

was holding onto positive ground with its fingernails, up 4 to 2435 behind solid trading in

Intel

(INTC) - Get Report

and

Applied Materials

(AMAT) - Get Report

. Small-caps weren't so lucky, with the

Russell 2000

down fractionally at 400.

TheStreet.com Internet Sector

index was up 5 to 610 and

TheStreet.com E-Commerce Index

was up a strong 3 to 113. E-Commerce Index component

Cyberian Outpost

(COOL)

was soaring 6 15/16, or 37%, to 25 7/16 on the launch of its new online computer auction site.

Market breadth was negative on both major exchanges.

New York Stock Exchange

decliners were outpacing advancers 1,412 to 1,110 on 213 million shares. On the

Nasdaq Stock Market

, 1,741 losers were leading 1,394 winners on 294 million shares.

New 52-week highs were ahead of new lows by 37 to 33 on the NYSE and by 52 to 46 on the Nasdaq.

Most active on the NYSE was

America Online

(AOL)

, up 2 7/8 to 104 13/16 on 9 million shares.

The Nasdaq's most active issue was

eFax

(EFAX) - Get Report

, up 8 7/8, or 41%, to 30 3/8 on 13 million shares. eFax was up after inking a pact to provide free fax-to-email service to

Xoom.com

(XMCM)

members. Xoom was down 4 11/16, or 7%, to 66 1/2.

9:50 a.m.: Dow Inches Toward 10,000

Stocks inched higher in the early going, as the

Dow Jones Industrial Average

gained 21 to 9980, crawling ever closer to the 10,000 level.

The Dow got a boost when component

Union Carbide

(UK)

began trading. It was up 2 1/2, or 6%, to 46. Union Carbide this morning said first-quarter operating earnings should come in within a few cents of the highest-published

First Call

analyst estimate, which is 47 cents. The current 10-analyst consensus estimate has Union Carbide earning 34 cents a share in the first quarter.

Elsewhere, the

S&P 500

was up 3 to 1310.

The

Nasdaq Composite Index

was up 5 to 2436. The

Russell 2000

was up 1 to 402.

TheStreet.com Internet Sector

was up 10 to 615.

TheStreet.com E-Commerce Index

was up 5 to 115.

The 30-year Treasury bond was up 4/32 to 96 5/32, yielding 5.51%.

Most Up at Open -- NYSE

Teradyne (TER) - Get Report, up 2 9/16 to 54

.

Most Up at Open -- Nasdaq

Go2Net (GNET) , up 14 5/8 to 128

: Paul Allen, co-founder of

Microsoft

(MSFT) - Get Report

, said yesterday he would invest up to $750 million in Go2Net for a controlling stake in the company.

Most Down at Open -- NYSE

Procter & Gamble (PG) - Get Report, down 1 3/16 to 90 1/2

.

Most Down at Open -- Nasdaq

Xoom.com (XMCM) , down 2 5/8 to 67

: The company filed with the

Securities and Exchange Commission

for an offering of 4 million common shares.