As fund managers increasingly turn to sophisticated data streams to boost investment returns and produce greater operational efficiencies, it is critical that they understand the legal and practical risks posed by the use of big data. Issues surrounding material nonpublic information (MNPI) pose the greatest threat to firms. Managers must understand not only the misappropriation framework under the Securities Exchange Act of 1934, but also how the New York State Attorney General and regulators in the E.U. pursue insider trading claims. Additionally, whether engaging internally in web scraping or purchasing scraped data from third parties, managers must be conscious of contractual, intellectual property and tort claims that a site owner may allege against a fund manager. Finally, many of the largest challenges posed by the use of big data are practical or ethical in nature. This second article in our three-part series on big data analyzes issues and best practices surrounding the acquisition of MNPI; web scraping; and the quality and testability of data. The first article explored the big-data landscape and how fund managers can acquire and use big data in their businesses. The third article will discuss risks associated with data privacy, the acquisition of data from third parties and the use of drones, as well as recommended methods for mitigating those risks. For more on big data, see “Best Practices for Private Fund Advisers to Manage the Risks of Big Data and Web Scraping” (Jun. 15, 2017).