As far as analogies go in the financial markets, this one from Moody’s Investors Service is brutal: Active mutual funds are to landlines as passive funds are to mobile phones. That’s the takeaway from analysts led by Stephen Tu after seeing a record $369 billion pour out of long-term mutual funds in 2018, while flows into exchange-traded funds remained largely in line with recent years. That stark difference, Moody’s says, is “credit negative” for traditional asset managers and may “indicate a loss of relevance with clients.” Call it the Jack Bogle effect.