The actions and potential failure of prime brokers pose sizable threats to the well-being of fund managers. In 2008, insolvencies by prominent prime brokers such as Bear Stearns and Lehman Brothers imperiled a number of hedge funds. See “Hedge Funds Turning to Prime Brokerage Trust Affiliates for Added Protection Against Prime Broker Insolvencies” (Jun. 24, 2009). In addition, as recently as July 2016, Merrill Lynch agreed to pay a $415 million settlement to the SEC in connection with actions that threatened its hedge fund clients. See “Merrill Lynch Settlement Reminds Hedge Fund Managers to Be Aware of How Brokers Are Handling Their Assets” (Jul. 7, 2016). In an effort to help our subscribers mitigate the risks posed by their prime brokers, this three-part series outlines steps that fund managers can take when engaging a prime broker. This first article details preliminary considerations when engaging prime brokers, including regulatory protections, several types of arrangements based on fund risk profiles and due diligence efforts managers can undertake. The second article will examine structural considerations to mitigate prime broker risk, including the viability of multi-prime and split broker-custodian arrangements. The third article will describe legal protections that can be included in prime brokerage agreements to mitigate risk, including with respect to rehypothecation limits and asset transfer restrictions. For more on prime broker selection, see “Factors to Be Considered by a Hedge Fund Manager When Selecting a Prime Broker” (Dec. 4, 2014); “How Should Hedge Fund Managers Select Accountants, Prime Brokers, Independent Directors, Administrators, Legal Counsel, Compliance Consultants, Risk Consultants and Insurance Brokers for Their Funds?” (Jun. 13, 2013); and “Prime Brokerage Arrangements From the Hedge Fund Manager Perspective: Financing Structures; Trends in Services; Counterparty Risk; and Negotiating Agreements” (Jan. 10, 2013).