The investor who anchors a round by setting the valuation, writing the biggest check, and usually taking the board seat, with everyone else filling in around their terms.
In June 2021 Klarna closed a $639M round led by SoftBank's Vision Fund 2 at a $45.6B post-money valuation, with Sequoia (already a long-standing lead from earlier rounds) participating. Sequoia had led the Series A back in 2010 and stayed in the lead seat on multiple subsequent rounds, illustrating how a lead investor relationship often extends across the company's entire private life, not just a single financing.