Moody's Investors Service said Monday that the weak return on Harvard University's $30.7 billion endowment, which the university announced last week had shrunk 0.05 percent in the 2012 fiscal year, is a bad sign for endowment-dependent universities. The rating agency said the results probably won't affect Harvard's rating, but are likely to lead the institution and others to rethink their dependence on endowments. "Based on highly variable investment returns over the past decade, we expect endowment-dependent institutions to make more conservative spending decisions for future fiscal years and to more fully assess their operational vulnerability to investment volatility," the agency wrote. "Budgetary models are increasingly stress tested, and management teams are adjusting to more conservative assumptions about long-term rates of return on their endowment. Many have lowered their assumed annual endowment returns to 7 percent to 8 percent, compared to the higher 9 percent to 10 percent return assumptions that were common prior to 2009."