danholt4mac (http://macte.ch/ggDRI) says (iStockEx (formerly called iStock) is now available at the Mac App Store.

iStockEx is a portfolio manager for private or professional use. You can set up as much portfolios as you want and track the performance of your shares in real time. iStockEx continuously retrieves the latest quotes from the Internet and updates automatically the value of your assets.  You can y enter your sells and buys and watch your portfolios including calculation of gain or loss in a convenient format, all done in your local currency.

For the launch of iStockEx on the Mac App Store its price has been reduced: You can now buy iStockEx for only US$4.99; previously, it was $19.99.