How should retirees invest in the current market

Following the Fed’s report that people over age 75 are the most likely to own stocks, I am looking for experts who can provide guidance and commentary on how retired people should be investing in the current market. Why do you think people over 75 are so much more likely to own stocks? Which investing strategies are best suited for retired people in the current market? How would you characterize the current market and what do you expect to see in 2018? What investing risks should retired investor watch out for in 2018? Is there any conventional wisdom about retirees and the stock market that no longer applies? Anything else you’d add about investing during retirement?