Investing Update | April 30, 2012 In what seems like a weekly occurrence, Colombia's state-controlled oil company Ecopetrol (EC) reported a discovery Wednesday at an exploratory well in its decades-old Tisquirama block in the northern state of Cesar. For more about Ecopetrol and another new Colombian stock, read the attached weekly update for April 30th if you have not already downloaded it. The other big news comes from Argentina where the lower house of the legislature is expected to pass an expropriation of 51% of the YPF shares on Wednesday. Apparently nervous about government moves to take control of petroleum firm YPF SA (NYSE:YPF), investors pushed Argentina's Merval stock market gauge down 2.8% for the week after it tumbled 6.5% a week earlier. But after crashing 33.63% a week earlier, YPF's stock price retreated a more modest 2.88% in the latest week. The stock's U.S. ADR price seems to have stabilized at the current $14 level for the time being. And other Argentine issues suffered steeper setbacks too, including Petrobras Argentina SA (NYSE:PZE), McDonald’s franchisee Arcos Dorados Holding (NYSE:ARCO) and agricultural firm Cresud Inc.(NASD:CRESY), each of which skidded more than 6% during the week. Bucking the tide was e-commerce firm MercadoLibre (NASD:MELI), which advanced 4.83%. It's clear that the government very much needs private investors and will not be taking ownership of the 49% it does not own. Interestingly, the biggest risks here are demands from YPF on the other public shareholders and threats for more lawsuits to YPF. If you can not see the file download button and link below for this posting it is because you are not logged in. Login or subscribe to see and download the latest trade ideas. It takes only 2 minutes to subscribe.