Shares of Amazon.com Inc. AMZN sank 2.8% in morning trading Thursday, putting them on track to suffer a sixth-straight decline, after three executives were added to the Federal Trade Commission’s lawsuit against the ecommerce and cloud giant. The stock has tumbled 9.2% during its current losing streak, which would be the longest since the six-day stretch that ended Feb. 10, 2023. The losing streak started after the stock closed at a 17-month high of $144.85 on Sept. 13. The stock has been pulling back amid increasing expectations that the FTC will file a major antitrust lawsuit against Amazon. But D.A. Davidson analyst…