Perplexity AI Inc., an artificial intelligence startup building a search product to compete with Alphabet Inc.’s Google, has closed a $500 million round of funding that triples the company’s valuation to $9 billion, according to a person familiar with the matter. The round was led by Institutional Venture Partners and completed earlier this month, according to the person, who asked not to be identified discussing private information. Perplexity declined to comment. Even by the lofty standards of...