SpaceX (SPCX) Declines for Second Day, Amazon (AMZN) Reclaims Market Cap Lead

SpaceX (SPCX) shares fell 3.57% on June 18, 2026, marking a second consecutive day of declines as post-IPO enthusiasm cooled. The aerospace company's market capitalization dropped to $2.43 trillion, falling behind Amazon (AMZN). Amazon shares rose 2.9% on June 18, 2026, closing with a market cap of $2.63 trillion, reclaiming its position as one of the highest-valued U.S. companies. This follows SpaceX's brief period earlier in the week of June 16, 2026, when its valuation temporarily surpassed Amazon and even Microsoft (MSFT). The decline on June 18, 2026, came after a 5% drop on June 17, 2026. Despite the two-day pullback, SpaceX shares remain up approximately 15% for the week ending June 19, 2026, and are still 37% above their $135 per share IPO price from the week of June 9, 2026. Separately, SpaceX announced on June 17, 2026, that Roelof Botha joined its board as an independent director.