A clear pattern: Walmart earnings call warns short.

After every Walmart earnings call from the past 5 years has a decline of on average $5 that occurs within a week after earnings call. My method is as follows: A day before I bought a put option on Walmart which expires in 12 days. I will hold this put option for a maximum of one week and wait until WMT stock falls to about $145-$148 per share.