Well, SIAL was going steadily up since 2002. Why? The answer lies in the desciption of what company is all about:
"Sigma-Aldrich Corporation develops, manufactures and distributes a range of biochemicals and organic chemicals. These chemical products and kits are used in scientific and genomic research, biotechnology, pharmaceutical development, the diagnosis of disease, and as key components in pharmaceutical and other high-technology manufacturing. It operates in 35 countries, offers over 100,000 chemical and 30,000 equipment products and sells these products into over 150 countries."
Plus when all that you hear is reaching research deal with Pfizer, signed licensing agreement, raised revenue outlook, acquiring of other good companies, and opening more facilities in booming markets, all you want to do is BUY, BUY, BUY!
The downside is a stock growth of just 15% a year, but hey, you need to put some of your money in a safe place and SIAL provides just that.