By lending to risky borrowers, the companies are assuming larger amounts of risk that can lead to financial problems if the borrowers default on their loans. (lendedu.com)
This means for the expected return your portfolio would get, you would bear an unnecessarily large amount of risk. (money.stackexchange.com)
If you feel you have time, and a fairly large amount of risk capital (say, more than $ 100,000) you can have fifteen or twenty stocks in your portfolio. (invest-faq.com)