As far as I understand the SolidCoin idea, they want to give the ability to gain interest on funds you lock away for X months. So perhaps it's 3% if you lock your coins away for 12 months.
SolidCoin doesn't have a max coin potential like Bitcoin, but it's rate of generation depends on the amount of energy mining it. So this bond idea would be another way to give certain businesses a way to guarantee an increase in their SolidCoins which could then be used for more riskier investments. At least that's what I got from it.
Depends on what they mean by "higher risk". Lenders and investors generally avoid "high risk" investments for a reason. (see: CMBS)