Credit ratings agency S&P on Tuesday revised Mexico's outlook to "negative" from "stable", citing the risk of very slow fiscal consolidation largely due to weak economic growth that could lead to a faster-than-expected buildup in government debt and a higher interest burden. The agency said Mexico's low per capita growth remains a key ratings constraint, while soft economic activity, rigid spending and weak financial position of the country's largest public-sector companies are eroding fiscal flexibility and pushing up debt.