Why health care stocks are poised to lead gains in December

The health care sector has been the top performing S&P group so far this year. It's gained over 14 percent, through the end of November.

According to history, that momentum should carry through the end of the year.

Since 1990, after the health care sector has logged similar, double-digit gains through November, the bullish trend continues.

The index adds another 2.4 percent in the month of December.

And the positive, seasonal traction extends to the broader markets.

Stocks rallied on Monday after trade negotiations with China progressed.

Washington and Beijing agreed to a 90-day negotiation period beginning January 1.

This happened on the first trading day of December, historically one of the strongest months of the year for stocks.

Since 1990, stocks tend to close out the month of December firmly in the green.

The Dow and S&P 500 post gains in excess of 1.5 percent and the Nasdaq jumps 2 percent.

And small caps soar, with the Russell 2000 jumping 2.8 percent, a positive trade over 80 percent of the time.