There is no specific rate for venture capital loans. VC loans are very risky and therefore, the rate is more closely tied to the lender's evaluation of risk than to any market norms. Factors to be considered include:
What sort of business is it?
What is the owner's track record with other businesses?
What is the prior performance of this business?
Is the VC lender getting equity in the business?
Does the VC lender get a preferred return upon liquidation?
In what industry is the business?
What is the projected performance of the business?