S&P 500 heads for winning week, but late selling knocks down benchmark on Friday

The S&P 500 pulled back from a record high on Friday as Wall Street headed for solid weekly gains even with a U.S. government shutdown dragging on.

The broad market index hovered around the flatline, while the Nasdaq Composite fell 0.4%. The Dow Jones Industrial Average outperformed, trading higher by 319 points, or 0.7%. The Russell 2000 also popped more than 1%. All four benchmarks had hit all-time highs earlier in the session.

Stocks came under pressure in afternoon trading, bogged down by key technology names like Palantir Technologies, Tesla and Nvidia. Palantir led the S&P 500 lower, falling 7%, while Tesla and Nvidia dropped 3% and 1%, respectively. The CBOE Volatility Index spiked Friday afternoon, signaling some investors were scrambling to buy some protection against a future S&P 500 decline in the form of put contracts.

Still, the three leading indexes are pacing for a positive weekly finish. The broad market S&P 500 has risen more than 1% week to date, along with the 30-stock Dow and the tech-heavy Nasdaq. The small-cap Russell has jumped more than 2% in the period.