Basic Materials and Energy have been the leading sectors so far this week, as the overall market continues to seek support, as well as leadership for moving higher. But the dollar seems determined to spoil the party.

Basic Materials and Energy sectors returned to a leadership role today as the stock market looked to bounce from its recent doldrums. Both sectors advanced about 2%. However, it is Healthcare that has remained consistently strong. And in fact, it is Healthcare that has maintained a steadily strong score in Sabrient’s quantitative SectorCast model.

We have all heard the old Wall Street adage to “sell in May and go away” until October, as the market historically underperforms in the May-September timeframe. And indeed, after the “bin Laden gap up” at the open on Monday, stocks quickly turned tail. Today, the selling intensified following the disappointing ISM Non-Manufacturing Index for April, with Energy and Materials the hardest hit.

For the first time in the 98-year history of the Federal Reserve, its chairman held a news conference after its FOMC policy meeting. So, what was the big news? QE2 will end in June as planned, but as I speculated last week, they will keep the balance sheet steady by continuing to reinvest maturing assets into the debt markets. They will also keep the Fed Feds Rate in the 0.00-0.25% range. Both of these are stimulative to the economy.

In my weekend analysis, I talked about the possibility of a bullish reverse head-and-shoulders formation for the stock market. And after allowing for a brief panic on Monday, the market has been quite strong this week and appears to be confirming the bullish pattern.

Last week I mentioned that a pullback was due, and indeed we’ve seen some market weakness this week. The 50-day simple moving average is trying to support the large, mid, and small caps at this point, but the Dow Industrials and MSCI Emerging Markets are holding up better as they are supported by their 20-day. Among the major sectors, Healthcare has actually displayed strength this week despite overall market weakness.

Although trading volume remains anemic, with NYSE volume below 900 million today, equity bulls continue to run the show as the global “wall of worry” seems to suit them just fine, thank you.

Bulls continue to shake off global challenges to keep the market in rally mode heading into the end of the first quarter, led by powerhouse sectors Basic Materials and Energy as well as Healthcare and upstart Telecom. In fact, the S&P 500 is on track to achieve its largest first quarter return since 1998. The SPY closed today at 132.77, up 5.6% on the quarter with one more trading day to go.