I have also been looking at this for a week or 2 and you are correct....no earnings until end of Sept..but Implied Volatility is at the 90+% percentile relative to its IV history and I just cannot find any reason for it.
Obviously it is a bunch of options screaming to be sold...But , like you, I feel there has to be a reason for this and I cannot find it....Just be sure to protect yourself when selling these High IV options
Pretty simple, the stock has run up on speculation about the tax inversion. It's not trading on biz fundamentals. So more unknowns/uncertainties leads to higher volume and higher volatility. This will go on until they announce the inversion one way or the other then you will have a $60 stock or an $80 stock.