Stock history for SDS is incorrect. ETF viewer says closing price for SDS on 6/4/2010 was $35.75. But when I right click and view the stock history. The end o day price for SDS for 6/4/2010 is shown as $35.62. I did this at 7:00 PM on 6/4/2010. $35.75 is the correct end of day price for SDS according to Google Finance so it appears your stock history chart is incorrect.