Apple Inc.'s stock AAPL, +3.03% tumbled 5.9% Friday, to enter bear market territory for the first time in over two years. The technology giant's stock closed at $106.05, or 20.3% below the Feb. 23 record close of $133. Many market watchers define a bear market as a decline of 20% or more from a significant peak. Based on current share counts, the company has lost $153.69 billion in market capitalization during that decline, according to FactSet. The last time Apple was in a bear market was when it plunged 44% from the split-adjusted Sept. 19, 2012 closing peak of $100.30 to the April 19, 2013 close of $55.79.