Investors never know for sure if a company is going to post better earnings results than expected. That’s why there are always earnings surprises. However, that doesn’t keep traders from making educated guesses. In the case of Amazon (AMZN), a trader recently purchased 17,000 bullish call spreads that expire the day after earnings come out. The strategy will pay off if AMZN’s stock price is over 15% higher at expiration compared to where it was at the time of the trade.