Fountain9 is a Y Combinator backed company that provides predictive inventory planning and optimization software for e-commerce, DTC, and retail companies. Their flagship product, Kronoscope, uses AI to accurately predict future inventory imbalances and recommends ways to minimize their impact. Kronoscope considers factors like historical sales trends, seasonality, holidays, markdown events, and pricing changes to optimize prices and predict inventory requirements. It also aligns predicted demand with supply side data to identify ideal suppliers and replenishment quantities, reducing stock outs and inventory wastage.