Some surprises can be nice — birthday parties, tax refunds, a winning lottery ticket. But others — car repairs, tax audits, root canals — are less welcome.

The stock market also has its surprises. Public companies are required to publish their earnings results quarterly, and if a number is not in line with expectations, it’s considered an "earnings surprise," which can significantly impact a stock’s price, positively or negatively.

Options traders need to pay particular attention to earnings reports because the results of earnings surprises are magnified in the option world: An earnings surprise that results in a 10-percent move in a stock’s price might move options on that stock significantly more.