10 things you need to know before the opening bell (SPY, SPX, QQQ, DIA, TWTR, AAPL)

Business Insider has launched Markets Insider, which combines the best of Business Insider with real-time market data. You can follow the site on Twitter @MktsInsider and on Facebook.
Here is what you need to know.
Obamacare will get a lot more expensive in 2017. On Monday, the Obama administration warned that premiums for plans under the Affordable Care Act, also known as Obamacare, would soar by an average of 25% next year.
Twitter is planning a round of layoffs. The social-media company is pl