Historically, the J curve effect has been more pronounced in the US, where private equity firms tend to carry their investments at the lower of market value or investment cost and have been more aggressive in writing down investments than in writing up investments. As a result, the carrying value of any investment that is underperforming will be written down but the carrying value of investments that are performing well tend to be recognized only when there is some kind of event that forces the private equity firm to mark up the investment.