The shoddy performance of high-cost hedge funds and mutual funds compared with the broader market has driven investors into low-cost “passive strategies” that track indexes.

But active fund managers are arguing that they can beat the market with better stock picks when the market declines, The Wall Street Journal reports.

“Even as evidence continues to mount that stock pickers have underperformed the market averages, active managers insist that they will make a comeback,” according to the newspaper. “Analysts at Bank of AmericaMerrill Lynch found earlier this month that 63% of active fund managers investing in large U.S. stocks outperformed their benchmarks in April, the best since February 2015.”

The S&P 500 has risen 2.5-fold since the March 2009 bottom, when the U.S. economy was suffering its worst economic contraction since the Great Depression. The Federal Reserve and central banks in Asia and Europe helped to lift the market with record-low interest rates and asset purchases as economic growth slowed to a crawl.

“The odds of finding a stock picker who can do better in down markets have long been less than 50-50,” according to the WSJ. “The brief periods in which active managers did resoundingly better than the S&P 500 have tended to be times in which small stocks outperformed large. If you or your financial adviser think stock pickers will prevail in the next downturn, the evidence isn’t on your side.”

CNBC’s Ron Insana fears that the controversy surround President Donald Trump and the firing of FBI Director James Comey amid a probe of alleged Russian influence of U.S. elections could ultimately be fatal to the recent stock bull market.

“I am among the few who believe that President Trump's term will be attenuated, much in the same way as Nixon's second. I can foresee many reasons why even Republicans will ultimately see an advantage in forcing Trump's resignation and working with a president named Pence,” Insana wrote for CNBC.com.

“If the Trump administration ultimately fails to survive the political turmoil that intensified, without warning this week, one could rightly assume that the stock market could be vulnerable to an extended pullback," wrote Insana, a CNBC and MSNBC contributor and the author of four books on Wall Street.

"It could easily suffer a 10 percent to 20 percent correction as a consequence of a constitutional crisis which may well be in the making,” Insana predicted.

“I would bet against Trump on this one and take some precautions in the market. Traders may want to protect their portfolios and simply raise cash. In addition, buying puts (a contract giving the owner the right, but not the obligation, to sell a specified amount of an underlying security at a specified price within a specified time) on the S&P 500 could be a profitable trade as disgruntled intelligence types leak more and more details about on-going investigations,” Insana advised.

“For longer-term investors, holding off on adding to existing stock market positions may make sense here, as stocks could be markedly cheaper later in the year. It seems this may well be a ‘sell in May and go away’ type year,” Insana wrote.