Stocks snapped an eight-day winning streak Friday, but still managed to finish up more than 1 percent for the week.
Telecoms and industrials were the week's best performers, while energy and materials were the worst.
Despite today's losses, all three major indexes — the Dow, S&P 500and Nasdaq — remain near their 18-month highs.
United Technologies had the most positive impact on the Dow this week, up nearly 2.5 percent; Boeing remains the blue-chip index's best performer for the year, up nearly 31 percent year to date.
Caterpillar had the most negative impact on the Dow this week, down over 1.5 percent.
Over on the S&P, GE had the most positive impact this week, up over 6 percent, while Google had the most negative impact, down nearly 3.5 percent.
In today's session, a fresh round of worries about Greece sent the dollar higher, which pushed oil prices and stocks lower. Also at work today was uncertainty over the health and financial-reform bills. And quadruple witching, the expiration of four key futures and options contracts, added another couple of layers of volatility to the market.
The tech-heavy Nasdaq was the hardest hit. Techs were down across the board, with Garmin, Applied Materials, Apple and Google among the biggest percentage decliners on the Nasdaq.
Palmshares tumbled nearly 30 percent as several analysts downgraded their ratings or price targets on the stock after the hand-held gadget maker's disappointing results. Company executives told analysts on a conference call Thursday that fourth-quarter revenue will be less than $150 million, compared with analysts' expectations of around $306 million, according to Thomson Reuters.
Boeing shares slipped 0.2 percent, giving back all of their earlier gains, after the aerospace giant announced plans to bump up production of two aircraft— the 777 and 747 — to meet increased demand.
Ford shares slipped over 3 percent after the Wall Street Journal reported that the chairman of China's Zhejiang Holding Group said talks to acquire Ford's unprofitable Volvo unit have been held up over unspecified issues at Ford.
Ford's shares earlier this week hit a five-year high after Moody's upgraded the automaker's debt and said its finances were likely to improve even more.
Car sales for March are accelerating past analyst expectations. An article in Friday's Journal says sales are picking up speed, and that even troubled Toyota is showing dramatic increases in sales as the month moves on.
Health-related stocks were also mixed as last-minute bargaining on the health-care reform bill continues. House Majority Leader Steny Hoyer told CNBC that he is "close" to securing enough votesfor passage of the bill. Right now, projections are that a vote may happen on Sunday afternoon.
Market pros said the prognosis for the health-care sector is good either way but Wall Street was a little rattled by provisions in the bill that increase taxes on high-income individuals and add new taxes on investment income.
"For investors and traders, the House passing the Senate version of the bill will be seen as a positive — but more for removing the uncertainty factor rather than a boost to the overall economy," said Todd Schoenberger, managing director at LandColt trading.
"Don't be surprised if you see a rally take place in medical device companies, labs, and health equipment manufacturers next week" if the bill passes, he said.
Aetna gained 3. 7 percent after the insurer said it expects first-quarter earnings to top Wall Street estimates, but held onto its prior forecast for the full year.
Wellpoint and Express Scripts also finished higher, while Merck and Pfizer ended lower.
Boston Scientific rose nearly 1 percent after the FDA approved a new use for Cardiac Resynchronization Therapy Defibrillators for use on patients with heart failures.