Not really any risk that I can tell.
I can tell you the cash you put out in loans is hardly gaining anything though. It seems odd that the interest is not charged on a game month basis..
The biggest risk I can see is doing what I did when I first started playing/ I thought I was rich, so I gave almost all my cash out in loans, but then I spent too much, got into some sort of an automatic buying spree on the military, and went into debt, negative cash - by the time I figured out the problem, I had to buy some GCs and buy cash with that to stay afloat until the loans came back.