After stock price gains earlier this month, health insurers saw shares dip, partly due to disappointing earnings reports, Barron's reported.
For Aetna, which missed its earnings expectations, technical indicators measuring momentum, relative performance and trend all took a dive this month.
And while shares of WellPoint are holding relatively stable, technical indicators show signs of weakness, according to Baron's, which also noted that after a month of stability, Cigna shares have made short-term downward moves in prices.
Even though UnitedHealth Group met analyst expectations for the third quarter, its earnings announcement was followed a 5.1 percent loss and then an additional 3.7 percent loss, the article noted.
However, in the 12 months leading up to Affordable Care Act implementation, Aetna, WellPoint, UnitedHealth Group, Cigna and Humana saw shares increased by an average of 32 percent, according to The New York Times.
That wasn't the case right after the Supreme Court ruled the reform law constitutional last June. Health insurance companies' stocks initially dove after the ruling, but most insurer stocks rebounded after it became clearer the decision generally favors health insurers, FierceHealthPayer previously reported.
As of last week, healthcare stocks have lost the lead in the race for the best performing sector of 2013, MarketWatch reported. Stocks for health insurance and medical treatment companies have fallen behind consumer discretionary stocks, which represent what consumers want, such as a new car, vacations, retail therapy or entertainment.