Perplexity is raising new investment that would value the search startup at $9 billion, a source familiar with the matter said on Tuesday, a sign of heightened investor enthusiasm around artificial intelligence companies. California-based Perplexity is set to raise $500 million in the new funding round led by venture capital firm Institutional Venture Partners (IVP), which also holds a board seat in the startup, the source said. The company had raised $73.6 million in Series B funding in January.