43 is a "Day 0" pre-product fund that leads founders' first $500K–$1M institutional rounds with 5–7% ownership, limiting volume to about five investments per investor per year to maintain extremely high-touch, around-the-clock service relationships. The fund operates from a physical studio at 43 Dore Street in San Francisco and focuses exclusively on generalist software companies, combining decade-plus VC experience, deep people-ops expertise, and founder-level growth marketing knowledge to work side-by-side with founders to achieve product/market fit.