Vanguard Increases Stake as Solid Power Shares See Insider Selling Solid Power's stock opened at $1.10, with a notable transaction on March 6: CTO Joshua Buettner-Garrett sold 187,500 shares, reducing his holdings by nearly 18%. Despite this, 7.2% of the company remains insider-owned. The stock has experienced volatility, with a 52-week range between $0.68 and $2.70.123