German Finance Minister Wolfgang Schaeuble suggested that stricter rules governing financial products be implemented. "We must apply the rules of transparency to all market participants -- hedge funds and private-equity funds," Schaeuble said. "We should ban [over-the-counter] trade where possible, because we don't have transparency [in these markets]. And then we should try to regulate all innovative financial products. We cannot achieve everything through regulation, but we can try to tighten the rules."