The Dow Jones Industrial Average retreated from its elusive 20,000 milestone. The index ended the day roughly 100 points from that marker. Trading was quieter on Wall Street ahead of the Christmas break. GoPro  (GPRO - Get Report) had a wild day, spiking Thursday morning on whispers of a possible takeover offer. The action camera maker gave up most of those gains when those rumors turned out to be unsubstantiated. Trading volume was nearly double its daily average. Energy Transfer Partners  (ETP) jumped on reports private-equity firm Blackstone  (BX - Get Report) could take a stake in its assets. Sources indicate the stake could be valued at or above $5 billion. Red Hat (RHT) plummeted after its chief financial officer, Frank Calderoni, announced his resignation. The open-source tech company also issued weaker-than-expected guidance for its fourth quarter and full year.