John asked for your help regarding his plant to invest in the Philippine Stock Exchange. Currently, he has P1,000,000 extra money which he plans to invest in Jollibee Foods Corporation, expecting that...

John asked for your help regarding his plant to invest in the Philippine Stock Exchange. Currently, he has P1,000,000 extra money which he plans to invest in Jollibee Foods Corporation, expecting that the company will continue to perform well in the future. Is it advisable for John to invest all his money in just one company? Why or why not? Discuss.