Updated from 1:06 p.m.

Stocks returned to the red on Thursday afternoon after crude oil closed under $51 a barrel.

The S&P 500 was down 0.12%, the Dow Jones Industrial Average fell 0.14%, and the Nasdaq declined 0.15%.

Crude oil prices pulled back on Thursday after closing at the highest level since July 2015 on Wednesday. Prices had rallied after a weekly reading on domestic inventories from the Energy Information Administration showed a decline for the sixth time in seven weeks. Upbeat comments from Saudi Arabia, one of the largest producers in the Organization of Petroleum Exporting Countries, helped support prices.

Yet West Texas Intermediate crude oil fell by 2.3% to $50.43 a barrel.

Verizon (VZ - Get Report) fell more than than 2% after earnings and revenue declined in its third quarter. The telecom giant earned 89 cents a share over the quarter, a dime less than the same period a year earlier. Adjusted income of $1.01 a share beat estimates by 2 cents. Revenue fell 6.7% to $33.1 billion. Verizon said it faced a "challenging environment" over the quarter, adding 442,000 retail postpaid net additions. Consensus was for 773,000.

The telecom sector was the worst performer on Wall Street Thursday. AT&T (T - Get Report) , China Mobile (CHL) , Comcast (CMCSA - Get Report) and BT Group (BT) fell, while the iShares Dow Jones US Telecom ETF (IYZ - Get Report) slid 1.3%.

American Express (AXP - Get Report) climbed more than 10% after topping earnings estimates in its recent quarter. The credit card company earned $1.24 a share, 28 cents above forecasts. Revenue fell 5.1% to $7.77 billion, narrowly beating sales estimates.

Existing home sales jumped in September as a stream of first-time homebuyers entered the market. Sales rose 3.2% to an annual pace of 5.47 million in September, according to the National Association of Realtors. The median price of existing home sales rose 5.6% to $234,200. First-time homebuying reached a four-year high of 34%. Strong demand has driven activity in the housing market despite constrained inventory and high prices.

The European Central Bank opted to leave its monetary policy unchanged on Thursday. The ECB held its key rate at a record low of 0% for another month and expects to hold rates at current levels "for an extended period of time." The central bank also said it intends to hold its monthly asset repurchases of €80 billion ($87.6 billion) a month until March 2017, though it could extend the program if need be.

ECB President Mario Draghi said in a press conference that the latest data on the eurozone economy show "resilience" to global uncertainty. Data since the September meeting met the central bank's expectations. Draghi said the ECB remains committed to using all tools necessary to achieve its growth goals.

Draghi "really wanted to shut down any suggestion that the ECB is going to taper any time soon, but what he actually did was to tell people to come back in December and see what the ECB thinks then," said James Athey, fixed income investment manager at Aberdeen Asset Management. "That will leave enough unanswered questions to keep bond markets volatile. An already nervous market will not take much comfort from his obfuscation today."

The number of new claims for unemployment benefits hit a six-week high in the past week, climbing 13,000 to 260,000, according to the Labor Department. Economists had anticipated 248,000 new claims. The measure remains under 300,000 for its 85th week in a row, the best streak since 1970. The four-week average increased to 251,750.

Business activity in the Philadelphia region fell in October, according to the latest Philly Fed Business Outlook. The index fell to 9.7 in October, down from 12.8 in September, but above forecasts of 5.3.

eBay (EBAY - Get Report) was down more than 11% after issuing disappointing guidance for its current quarter. The auction site said it expects adjusted earnings between 52 cents and 54 cents a share on revenue of $2.36 billion to $2.41 billion. Analysts anticipated adjusted earnings of 54 cents a share on revenue of $2.40 billion.

Kinder Morgan (KMI - Get Report) rose 2% despite reporting a surprise loss in its third quarter. The energy infrastructure company reported a net loss of a dime a share, far worse than an expected profit of 16 cents a share. Revenue tumbled 10.2% to $3.33 billion.

Mattel (MAT - Get Report) moved 6% higher after reporting a mixed third quarter. The toymaker earned 70 cents a share over its recent quarter, missing estimates by a penny. Revenue inched 0.6% higher to $1.8 billion, $30 million higher than analysts anticipated.

Travelers (TRV - Get Report) reported a decline in net profit in its third quarter tied to increased weather insurance claims. Net income fell to $2.45 a share from $2.97 a share in the year-ago quarter. Adjusted earnings of $2.40 a share edged past estimates of $2.38. Revenue increased 2% to $6.96 billion, exceeding estimates, as net written premiums rose 3%.

Walgreens (WBA - Get Report) rose more than 4% on Thursday despite missing analysts' quarterly estimates on its top line. The retail and pharmacy chain earned adjusted net income of $1.07 a share, 8 cents higher than consensus. Revenue rose just 0.4% to $28.64 billion, missing estimates of $29.11 billion. Walgreens also noted that its purchase of Rite Aid (RAD - Get Report) was "progressing as planned."

Walgreens is a holding in Jim Cramer's Action Alerts PLUS Charitable Trust Portfolio. Want to be alerted before Cramer buys of sells WBA? Learn more now.

Expedia (EXPE - Get Report) was upgraded to overweight with a $160 price target at Pacific Crest. The firm said its Homeaway unit was driving growth and that the company has multiple potential earnings levers.

AMC Networks (AMCX - Get Report) was downgraded to sector weight from overweight at Pacific Crest. Analysts said the company is leveraged to secular advertising pressures.

Presidential frontrunner and Democratic candidate Hillary Clinton faced off against Republican presidential candidate Donald Trump in the third and final debate Wednesday night. Trump added to concerns surrounding his candidacy after refusing to say whether he would concede a loss to Clinton if the polls pointed to his defeat after the results come in on Nov. 8. Trump's remarks came near the end of the final presidential debate when moderator Chris Wallace pressed the Republican nominee to explain his claims that the election will be "rigged" and whether he would abide by the result.