Lynn

Understanding Levered ETFs and Geometric Returns

Kunst,
On 9/24/08 SSO and SDS went exDividend. SDS distributed 6% of NAV as capital gains, while SSO distributed 0.45% of NAV. This would account for the wide discrepancy in their daily return on that day.
Also, SDS is currently trading at a premium of 7.27% and SSO is trading at a discount of 6.74%. You need to take this into account when comparing their daily returns.
I hope this helps.