Yellen bows out with a warning shot to stock market - Reuters

"stock market valuations are elevated beyond their usual historic levels, including the ratio of price to earnings", outgoing Federal Reserve chair Janet Yellen warned in the NewsHour interview recorded on Friday. "Yellen stopped short of characterizing the market’s rise in recent months as a bubble", the PBS News report says. 

Key quotes (Source: PBS News)

Investors should be careful and, I would say, diversified in their investments. 

Almost all groups in the American economy … you’re seeing plentiful jobs and wages beginning to rise at a slightly faster pace.

Productivity has been weaker than hoped.

The pace of new firms being created over the past decade was slower than usual.