I have an assignment asking for the rate of return on stock and corporate bond holdings and it indicated that I need to look at each

I have an assignment asking for the "rate of return on stock and corporate bond holdings" and it indicated that I need to look at each companies 10-k reports (there are 5 companies in total). I'm kind of confused on what information I'm supposed to be gleaning from the annual reports to determine the rate of return. I know that the rate of return is calculated by Current Price - Original Price / Original Price x 100. But I've searched the different companies' annual reports and nothing is listed as "corporate bond holdings" and stock prices can be found on google finance or yahoo finance, so why would I need to look at the 10-k reports like the rubric indicates? Can you lend any clarity to what the assignment might be asking for? Thanks