With a blistering first quarter safely in the record books, the Dow Jones Industrial Average (INDEX: ^DJI) kicked off the Q2 on a more inauspicious note, finishing essentially unchanged, down 0.04%. The two other major indexes were less successful, however, as the S&P 500 was off 0.5% and the Nasdaq dropped 0.9%. Trading volume was the second lowest of the year today as investors came back from the Easter holiday weekend and await earnings season, starting next week.

The general pullback in stocks seemed to come from a poorer-than-expected manufacturing report from the Institute of Supply Management. The ISM manufacturing index dropped to 51.3 in March, its worst level in three months, down from 54.2 in February and below projections of 54.0. The new orders rating fell 5.4 points to 52.2, while the employment index showed a slight improvement. Any reading above 50 indicates expansion so the report still shows slight growth.

UnitedHealth (NYSE: UNH) was the big winner on the Dow today, jumping 3.1% in regular trading hours, nearly all of it toward the end of the day and added another 3.9% after hours. The rally for the normally sleepy stock was sparked by a beneficial ruling from the Centers for Medicaid and Medicare Services as Medicare Advantage payouts will increase next year rather than decline, as some had feared. Instead of a 2.2% cut to the payout, which was proposed in February, insures will receive a 3.3% increase. Health insurance stocks jumped across the board including Humana, up nearly 18% in total, and Aetna and WellCare Health Plans, which each gained 5%.

Dragging down the laggards today was Intel (NASDAQ: INTC), which dropped 1.9% after two analyst downgrades. Alex Gauna of JMP Securities lowered his rating from outperform to market perform, suggesting that the chip maker may suffer delays in its microprocessor upgrade. The company responded, saying the project was "healthy and on track" and that "there's no problem at all." Meanwhile, another analyst said Intel could lose substantial market share in the Linux server market.

Outside the Dow, Apple (NASDAQ: AAPL) was again weighing on the broader market, forcing the S&P 500 and Nasdaq lower as shares of the IPhone maker fell 3.1%. CEO Tim Cook again reminded the investing world that he's not Steve Jobs, apologizing once more for one of the tech giant's mistakes. This time, he told Chinese consumers that his company was "arrogant" in its decision to provide them a shorter service warranty than in other countries after Apple spent two weeks getting bashed in the Chinese state-run media. Earlier in the day, Apple's largest shareholder, Fidelity Contrafund, also revealed that it cut its holdings by 10% in the first two months of the year.

Finally, Tesla (NASDAQ: TSLA) shares were roaring today, climbing 16% after the electric-car maker projected a surprise Q1 profit, and said sales of its Model S sedan totaled more than 4,750 for the quarter, when only 4,500 shipments had been projected. The analyst consensus had been a $0.07 EPS loss for the quarter.