We had a very interesting session today, led by Nasdaq. The market gapped up, pulled back in a bullish-looking manner early on, and then exploded to new 6-year rally highs on the S&P and all-time highs on the Dow. Nasdaq, of course, was far from it, but still had a very strong morning, fed by the Philadelphia Semiconductor Index (SOXX), which ran up at one point more than 10 points.

The NDX at that point was up nearly 25, but after about three hours of consolidation late morning into early afternoon the indices attempted a breakout, which only was able to retest the highs. When they failed to punch through, they began to roll over, accelerated lower in mid-afternoon and plunged with about an hour and a half to go. At that point they reached secondary support and then bounced fairly sharply into the last hour, putting the blue chip indices back in the plus column.

The Dow was up 0.56 today, and the S&P 500 did manage to get back into the plus column by a tad more than 2 points. The NDX, however, was the story, up nearly 18, with the SOXX up 7.40.

Advance-declines were not spectacular at all, only 3 to 2 positive on both exchanges. And up/down volume on New York was barely positive by just 7 to 6 . However, the story on Nasdaq today was the up/down volume of about 3 to 1 positive on more than 2.1 billion traded. The NYSE traded a total of about 1.4 billion.

TheTechTrader.com board was fairly narrowly mixed today, with only a couple point-plus gainers, both Chineses stocks. Those were XING, advancing 1.06 on nearly 1 Ã,¾ million, and Home Inns & Hotels (HMIN) up 1 on 630,000.

Other gainers of note, it was a significant day for Israeli tech Alvarion (ALVR), breaking out across a 2-year downtrend and key lateral resistance, up 85 cents on 4.1 million.

Portfolio position Aluminum Corp. of China (ACH) advanced another 50 cents today on over 900,000. GigaMedia (GIGM) popped 85 cents to new highs on 2.4 million. Global Sources (GSOL) closed at 20, up 85 cents on nearly 200,000. And Chart of the Week HTI popped 45 cents on 875,000.

Other stocks of note, Medialink (MDLK) to a new six-year high at 7.80, was up 26 cents. OSI Systems (OSIS), a former Chart of the Week, tested 25, closing at 24.94, up 92 cents, a new multi-year high. And Sigma Designs (SIGM) pushed through 27 today, closing at 27.19, up 59 cents.

On the downside, the big loser today was U.S. Global Investors (GROW), which had snapped back sharply recently from big losses, but rolled over by nearly 7 from high to low, closing down 4.83 on the day on 1.9 million.

Other losses of note, Chindex (CHDX) backed off 85 cents, the US Oil Trust (USO) oil ETF was down 93 cents on a downside reversal in oil. And Gmarket (GMKT) fell 47 cents.

Stepping back and reviewing the hourly chart patterns, breakouts did occur from the short-term basing-type pattern on the NDX and to the new highs on the S&P and Dow, but the afternoon downside spike, which was followed by a strong snapback, leaves the situation still in doubt.

On the other hand, support did hold, which leaves encouragement for the bulls. We’ll see which way they want to take this over the next days, but we’re reaching a critical point here.

Harry Boxer is a technical consultant to many Wall Street hedge funds and large institutional traders, and author of TheTechTrader.com, a real-time diary of his day, swing and intermediate-term trades. For more of Harry Boxer, sign up for a free 15-day trial to his Real-Time Technical Trading Diary, or sign up for a free 30-day trial to his Top Charts of the Week service.