Wall Street's bull market starts to show its age By: CNBC.com News April 22, 2014 at 18:40 PM EDT The bull market is seeing the equivalent of its first gray hairs and the proof is in Tuesday's blast of merger activity. Read More >> Related Stocks: Amtd Idea Group Apple Boeing Co Delta Air Lines Dow Chemical EMC Corp Facebook Genl Dynamics Ingersoll-Rand Plc LPL Financial Holdings Inc Motorola Solutions Norfolk Southern Northrop Grumman Procter & Gamble Qualcomm, Inc. Sentinelone Inc Cl A Texas Instruments Twitter, Inc. Valeant Pharmaceuticals International, Inc. Zynga Inc Cl A