The law states that the investment must be “at risk” meaning that the return cannot be guaranteed. However, this does not mean that the investment has to be overtly “risky”.
An "at risk" investment means that there is no guarantee that your money will be returned to you. An EB-5 Investor may not loan the required investment to the new commercial enterprise, and cannot receive a bond, note, or other debt arrangement from the enterprise in exchange for the contribution of capital. Most Regional Center Investments are tailored to maximize the probability that the investor receive a grant of permanent residency and are not meant to maximize profit generated from the investment.
For the invested capital to be at risk in a commercial sense, it must be subject to both gain and loss. It must be fully committed to the new commercial enterprise for job creating purposes.
Some regional centers even pledge (non-cash and non-liquid) assets or goodwill related to the project against some or all of investors' investments. The investment is still considered to be 'at risk' because the asset itself may be at risk of a loss in value. Certainly something to discuss with one's attorney before putting into practice.
An "at risk" investment means that it is a real investment instead of some bogus arrangement just to get a greencard.