Updated from 10:03 a.m.

Stocks slipped lower on Wednesday, putting the 20,000 milestone farther out of reach for the Dow Jones Industrial Average

The Dow dropped 0.12%, while the S&P 500 fell 0.36% and the Nasdaq declined 0.52%.

The dip helped prolong days of speculation about when the Dow might reach 20,000, a historic high. The index of 30 blue-chip stocks stretched to within 19 points of the milestone on Wednesday, before retreating. The Nasdaq slid from a record opening of 5,499.

All 11 S&P sectors were lower, with information technology and real estate as the biggest losers. Goldman Sachs (GS)  led the Dow, up 0.9%, and Boeing  (BA)  dragged down the index, falling 0.8%. 

Crude oil prices started off in positive territory for the fourth consecutive day as investors anticipate lower production in global oil supplies based on an agreement by the Organization of Petroleum Exporting Countries. West Texas Intermediate crude oil climbed 0.33% to $54.08 a barrel on Wednesday. Brent crude, the global benchmark, traded at $56.39, up 0.53%.

On the economic calendar, the November pending home sales index declined 2.5% from the prior month, according to the National Association of Realtors.

U.S. prosecutors charged three Chinese citizens with hacking into law firms to obtain confidential information on deals involving Intermune (ITMN) and Roche; Intel (INTC) and Altera; and Pitney Bowes (PBI) and BorderFree. The hackers were said to have made $4 million in in profits on trades related to about five companies.

Qualcomm (QCOM) was fined 1.03 trillion won ($853 million) by the Korean Fair Trade Commission. The watchdog said that the digital communications technology company violated antitrust and competition laws with its patent license agreements. Qualcomm general counsel Don Rosenberg said the company disagreed with the findings and will appeal the decision. Shares of Qualcomm were down 1.3% to $66.34 in trading Wednesday.

Delta Air Lines (DAL) said that it reached an agreement with Boeing to cancel 18 Boeing 787 Dreamliner aircraft orders. Based on list prices, the aircraft order was valued at $4 billion. Delta inherited the orders when it combined with Northwest Airlines in 2008.

"This business decision is consistent with Delta's fleet strategy to prudently address our wide body aircraft needs," Greg May, Delta's senior vice president for supply chain management and fleet, said in a statement.

Shares of Boeing fell 0.8% and Delta's shares fell 1.3% following the news.

BP (BP) shares were up 0.6% after announcing the purchase of Australian retailer Woolworths in a deal worth 1.79 billion Australian dollars ($1.29 billion).

Galena Biopharma (GALE) , which specializes in hematology and oncology therapeutics, saw its shares soar more than 42% when the company announced it received regulatory confirmation after meeting with the U.S. Food and Drug Administration about its GALE-401 Phase 3 trial. The trial is expected to start before June of next year. 

Toshiba (TOSYY) shares were in focus again after the company said Tuesday that its U.S. nuclear operation might record billions in losses. Shares of Toshiba fell 20%, and trading was halted in Tokyo.