NEW YORK (Reuters) - U.S. stocks dipped on Friday as investors were cautious ahead of the first round of the closely contested French presidential election, but the S&P 500 managed to notch its first weekly gain in three.

The first round of France’s presidential election may be too close to call when polls close on Sunday because initial projections will not be available as early as in the past, pollsters and their watchdog said.

Most polls see centrist Emmanuel Macron and far-right leader Marine Le Pen qualifying on Sunday for a May 7 runoff, but conservative Francois Fillon and leftist Jean-Luc Melenchon are not far behind and within the margin of error.

“Nobody is taking anything for granted after the big swing and miss in Britain and the big swing and a miss here,” said Jack Ablin, chief investment officer at BMO Private Bank in Chicago.

“I don’t think anyone wants to stick their neck out for this one.”

U.S. President Donald Trump said he would have a major tax reform announcement on Wednesday.

The Dow Jones Industrial Average .DJI fell 30.95 points, or 0.15 percent, to 20,547.76, the S&P 500 .SPX lost 7.15 points, or 0.30 percent, to 2,348.69 and the Nasdaq Composite .IXIC dropped 6.26 points, or 0.11 percent, to 5,910.52.

Traders work on the floor of the New York Stock Exchange (NYSE) in New York, U.S., April 20, 2017. REUTERS/Brendan McDermid

For the week, the Dow rose 0.5 percent, the S&P gained 0.8 percent and the Nasdaq advanced 1.8 percent in what was the first weekly gain for the top indexes over the last three weeks.

A steady stream of strong earnings through the week helped to buoy market sentiment.

Of the 95 companies in the S&P 500 that have reported earnings through Friday morning, about 75 percent have topped expectations, according to Thomson Reuters data, above the 71-percent average for the past four quarters.

Overall, profits of S&P 500 companies are estimated to have risen 11.2 percent in the quarter, the most since 2011.

Shares of General Electric GE.N fell 2.4 percent to $29.55 after the company reported negative cash flow from its industrial operations in the first quarter. The stock was the biggest drag on the S&P 500.

Schlumberger SLB.N lost 2.2 percent to $74.84. The oilfield services provider warned that margins would remain under pressure as it spends more to bring back idled equipment.

Mattel MAT.O tumbled after the toymaker reported a bigger-than-expected quarterly loss. The stock closed near its session low, down 13.6 percent at $21.79.

Federal Reserve Vice Chair Stanley Fischer told CNBC that the central bank remains on track for two more interest rate increases this year despite some soft economic data recently.

Declining issues outnumbered advancing ones on the NYSE by a 1.19-to-1 ratio; on Nasdaq, a 1.40-to-1 ratio favored decliners.

The S&P 500 posted 28 new 52-week highs and 1 new low; the Nasdaq Composite recorded 92 new highs and 39 new lows.

About 6.40 billion shares changed hands in U.S. exchanges, slightly above the 6.31 billion daily average over the last 20 sessions.