Pension funds, and other non-traditional lenders, are eagerly eyeing investment opportunities in Asia's booming infrastructure sector. On paper, it looks a good fit. Mega-projects are underway across this developing region, including road-building and electricity programs.Traditionally, global pension funds have favored infrastructure sectors, given the probability of stable, long-term returns. But that isn't as certain in Asia. Economic and sovereign risks can vary enormously among Asian countries, and potential lenders may conclude the risk-rewards aren't high enough. Standard & Poor's Ratings Services also believes the stranglehold of Asian banks on infrastructure funding may prove hard to break. For those reasons, global investors aren't making the same headway into infrastructure financing as they are in the U.S. and Europe.