Question:

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”.

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.