Your chart shows XIV had 90% in 1903, which could not be true.There were no options, nor VIX at that age. BTW, SVXY never had a reverse split. Don't compare SVXY with VXX, they are opposite entities. What caused VXX reverse split, has caused SVXY to continue going up.
I think I've said "...the dates are obviously wrong...". I have simulated data for VXX/UVXY/XIV since 2004, if you are interested.
Can anyone point to a reliable source of weekly or monthly data for SVXY? Proshares website says the inception date was 10/3/2011 but Yahoo! Finance data only goes back to 2014. I can get the daily performance from ProShares but converting that to weekly or monthly data is a pain I'd rather not endure.