Stock Trading History of Chang Michael N

The following table details the trading activities (stock purchases, stock sales, and stock option exercises) reported to the Securities and Exchange Commission (SEC) by insider Chang Michael N since year 2005. The trader's CIK number is 1380901. At the time of this reporting, Chang Michael N is the CEO and President of Optimer Pharmaceuticals Inc . (stock ticker symbol OPTR). See this page for all insider trading activities at Optimer Pharmaceuticals Inc .

Stock purchases, sales, and option exercises reported by insider *Chang Michael N* since 2005.
Trade Date	Symbol	Company Name (Issuer)	Trade Type	Shares	Price ($)	Value ($)
2008-06-13	OPTR	Optimer Pharmaceuticals Inc	Purchase	5,000	7.00	35,000
2008-05-15	OPTR	Optimer Pharmaceuticals Inc	Purchase	4,542	6.04	27,410
2007-11-15	OPTR	Optimer Pharmaceuticals Inc	Purchase	2,000	5.95	11,900
2007-08-09	OPTR	Optimer Pharmaceuticals Inc	Purchase	30,000	8.20	245,999
2007-08-06	OPTR	Optimer Pharmaceuticals Inc	Purchase	10,000	9.05	90,500
2007-07-16	OPTR	Optimer Pharmaceuticals Inc	Purchase	10,000	9.86	98,600
2007-02-14	OPTR	Optimer Pharmaceuticals Inc	Purchase	114,965	7.00	804,755

Insider trading activities including stock purchases, stock sales, and option exercises listed in the above table cannot be completely guaranteed as to their accuracy. For more information regarding the trades made by Chang Michael N (CEO and President of Optimer Pharmaceuticals Inc at the time of this reporting) see the Securities and Exchange Commission (SEC) website.