Be honest and forthright when answering this question. The hiring manager would like to further understand why you would, or would not, risk purchasing stock in the current market. You can complete your answer by asking the interviewer how they feel as well.
"Personally, I would be very cautious about buying stock in the market right now. With the recent election and the unsettled feelings surrounding it, I feel it would be wiser to sit back and wait a moment to see if any new trends begin to emerge. How do you feel about buying stock right now?"