YAHOO [BRIEFING.COM]: A strong favor for stocks today sent the major equity averages up to impressive gains. The advance has culminated in the Dow's best three-session performance since September.

Although an escalation of military engagement in Libya sent oil prices up more than 1% to close pit trade above $102 per barrel, news that Japan has made progress in its efforts to restore damaged nuclear facilities helped quell concerns about a potential meltdown. That helped both foreign markets and U.S. equity averages add to the gains that they staged late last week.

Despite the broad market's recent momentum, the S&P 500 struggled to extend its climb above the 1300 line. Meanwhile, the Dow worked its way to a new weekly high. That feat is owed to three straight advances, which have collectively made for a gain of more than 3%.

Dow component Caterpillar (CAT 107.59, +2.53) was a leader among blue chips as its shares set a record high, but AT&T (T 28.26, +0.32) led morning headlines with news that it will acquire T-Mobile from Deutsche Telekom in a $39 billion deal. The news won shares of T an upgrade from analysts at Citigroup. Shares of Sprint (S 4.37, -0.68) were shunned in response to the news.

The latest quarterly report from Tiffany & Co. (TIF 60.22, +2.93) made the stock a top performer. The company's news release featured an upside earnings surprise and upside guidance, which included consideration for the possibility of softer demand from Japan in the wake of the devastating earthquakes that stuck more than a week ago.

Supply and shipment concerns related to the wreckage in Japan had exacerbated recent weakness in semiconductor stocks during recent weeks, but the group rallied this session. Specifically, the 1.9% scored by the Philadelphia Semiconductor Index was its strongest single-session move in two weeks. Semiconductor stocks and large-cap tech helped lead the Nasdaq Composite this session.

News that Citigroup (C 4.44, -0.06) shares will undergo a reverse 10-for-1 stock split overshadowed the company's intention to reinstate its $0.01 quarterly dividend. Disappointment over the reverse split put pressure on the stock. That left shares of C to lag for the entire session, along with many other financials. The Financial Select SPDR ETF (XLF 16.34, +0.07) settled only modestly higher.

Favor for risk led to renewed selling against the greenback. In turn, the Dollar Index dropped to its lowest level since late 2009.

Treasuries were also clipped. They weren't helped by news that the Treasury will add to supply as it begins to wind down its $142 billion Mortgage-Backed Securities Portfolio this month.

It was a relatively quiet session for commodities, which finished mostly higher. Softs were the sole decliner, after shedding 0.5%.

Precious metals (+1.9%) was the largest advancing sector, led by a 2.8% rally in May silver, which closed at $36.00 per ounce. April gold ended higher by 0.8% to $1426.40 per ounce. A flight to safety and weakness in the dollar helped the precious metals higher today.

The implementation of the no-fly zone over Libya by a coalition of UN forces pushed April crude oil higher today. It gained 1.3% to finish at $102.33 per barrel. Continued unrest in other countries in the Middle East also captivated the market today. April natural gas finished just below unchanged at $4.16 per MMBtu.

The only item on the economic calendar was February existing home sales figures, which reflected annualized sales of 4.88 million. The consensus among economists polled by Briefing.com had been pegged at an annualized rate of 5.05 million. DJ30 +178.01 NASDAQ +48.42 NQ100 +1.5% R2K +2.3% SP400 +2.0% SP500 +19.18 NASDAQ Adv/Vol/Dec 2048/1.75 bln/574 NYSE Adv/Vol/Dec 2459/1.00 bln/547