Wall Street ended Monday’s volatile session slightly higher with help from technology stocks although bank stocks tumbled and uncertainty over Britain’s exit from the European Union kept investors on edge about global growth.

The Dow Jones Industrial Average lost as much as 507 points in early trading before recouping its losses and turning slightly higher in the afternoon. 

The energy index was the S&P’s biggest percentage loser as oil prices declined and financial stocks tumbled with the S&P 500 bank index confirming it was in bear territory.

But a comeback in Apple Inc shares appeared to cheer up investors in the broader technology sector.

Once the S&P neared its 2018 low - reached on Feb. 8 - trading algorithms appeared to kick in with buy signals, according to strategists. After hitting a session low late in the morning the benchmark spent the rest of the day paring losses at an uneven pace before turning positive.

“It seems we’ve found a temporary support at those levels. It might explain a little bit the reversal,” said David Joy, Ameriprise Chief Market Strategist. “It tells me it’s very short term computer driven trading, very choppy and directionless.”

British Prime Minister Theresa May added a wrinkle to global uncertainty on Monday by delaying a planned vote in parliament on her Brexit deal, saying it was set to be rejected “by a significant margin”.

“That adds to the political confusion that’s weighing on the market globally,” said Joy.

The Dow Jones Industrial Average rose 34.31 points, or 0.14 percent, to 24,423.26, the S&P 500 gained 4.64 points, or 0.18 percent, to 2,637.72 and the Nasdaq Composite added 51.27 points, or 0.74 percent, to 7,020.52. The Dow lost as much as 507 points in early trading before recouping its losses and turning slightly higher in the afternoon. 

After a sea of red in the morning, eight of the 11 major S&P sectors closed higher. The technology sector led the gainers with a 1.4 percent gain followed with a 0.8 percent increase in the communications sector

Energy stocks retreated 1.6 percent, the most among the 11 S&P sectors as oil prices fell. 

The second biggest decline was a 1.4 percent drop in financials as investors worried about the impact on slowing global growth and interest rates on banks. The rate-sensitive bank subsector tumbled 2.3 percent.

“What bank investors are doing is looking forward at what these guys are going to do for an encore as far as earnings growth goes,” said Sandler O’Neill analyst Jeffery Harte.

“If you look at the line items, credit probably can’t get much better. They’ve had interest rate tail winds. Loan growth seems to have slowed so the concern is what’s going to drive the next leg up.”

Apple Inc closed up 0.7 percent at $169.60 after hitting a low of $163.33 earlier in the day after Qualcomm Inc said it had won a preliminary order from a Chinese court banning the import and sale of several iPhone models in China due to patent violations.

The small-cap Russell 2000 also pulled above its session low to close 0.3 percent lower and was 16.9 percent below its record closing high on Aug. 31.

Declining issues outnumbered advancing ones on the NYSE by a 2.17-to-1 ratio; on Nasdaq, a 1.47-to-1 ratio favored decliners.

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The S&P 500 posted 4 new 52-week highs and 90 new lows; the Nasdaq Composite recorded 9 new highs and 383 new lows.

Volume on U.S. exchanges was 8.40 billion shares, compared to the 8.01 billion average for the last 20 trading days.