Shares of Tesla Inc. /zigman2/quotes/203558040/composite TSLA -5.26% tanked 3.8% toward a one-month low, which some technicians would say puts them on track to enter their third bear market this year. Many on Wall Street define a bear market as a decline of at least 20% from a recent bull market closing peak, and some say that bear market would end after a 20% rally off the subsequent low. Tesla's stock is currently trading 20.7% below its Nov. 4 record close of $1,229.91, and a bear market would become official to some technicians with a close at or below $983.92. The electric vehicle market leader's stock selloff has been highlighted by share sales by Chief Executive Elon Musk, who has sold roughly $11 billion worth of stock over the past month. Earlier this year, stock entered a bear market on Feb. 23, 2021, when it closed that day 20.9% below its then-record close of $883.09 on Jan. 26. That bear market bottomed on March 8 at $563.00, or 36.2% below its previous peak, before rallying as much as 35.4% to April 13 closing high of $762.32. The next bear market started in May, and bottomed on May 19 at $563.46, or 26.1% below the April peak. The current bull market started on June 24. The stock has still climbed 33.1% over the past three months while the S&P 500 /zigman2/quotes/210599714/realtime SPX -1.89% has edged up 0.7%.