I am trying to calculate IV of options for a ticker over the last 10 years. Problem is that some option prices don't make sense (for example, closing price \$31.94, but 30-day call option with 18 days ...
Yahoo's algorithm for adj.close calculation is pretty clear, as explained in the link. Said that, however, the values for RIG till 2007-11-26 don't follow such rules, as shown here. Indeed, if one ...