SEC filings show Heinrich Michael purchased 4,608,575 shares of ZSTK at $0.7549 per share, totaling $3,479,013.27. No other insiders reported buying ZSTK shares on July 20, 2026, making this the sole insider transaction for the day.
Large insider buys by senior executives can signal confidence in the company's outlook or valuation. Investors may view this as a notable event given the size and exclusivity of the transaction.