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Health funds saw a decline in 2016, specifically biotech and drug manufacturers, as the government has stepped up scrutiny on drug pricing practices, says Andrew Daniels, equity strategies analyst at Morningstar. Indeed, the health category tops the chart on mutual fund categories that declined in 2016. Health funds had been a top-performing sector for the previous several years, he noted, so it it's not surprising that some investors were looking for reason to take profits.

Bear funds also fell off a cliff in 2016. As a group, they were down more than 4% in 2015, but year-to-date in 2016, they've decline another 20%, not that surprising in a year when the S&P 500 posted gains of more than 10%. (This was originally posted in mid December.)

The bottom half of the list of declines was dominated by munis. New York and California each accounted for two categories, but Massachusetts, Pennsylvania and Ohio were also present and accounted for, as well as high yield munis.

To be sure, the first half the year was good for munis, but in the fall, worries of rate hikes loomed large and slowed gains. Then, Trump's surprise victory in November created uncertainty for fixed-income (although gave a boost for stocks) as expectations for more government spending has brought worries of higher inflation.

Scroll through to see the biggest declines, by category, in the markets. Declines were measured by the largest percentage point decrease in 2016 year-to-date performance over 2015 performance. Only categories with at least 10 funds were included. All data is from Morningstar.