WASHINGTON--The International Monetary Fund said Friday it has approved a second two-year credit line for Mexico worth $73 billion to help protect the burgeoning economy from external shocks.

The so-called "Flexible Credit Line" is for countries with strong economic fundamentals and helps assure markets the government has a sufficient backstop against crises such as an escalation of Europe's debt problems.

IMF Deputy Managing Director David Lipton said Mexico has robust monetary and budget policies that have supported the economy amid the global financial turmoil of the last five years.

"However, important risks to the global economic outlook remain, particularly from still unsettled international financial markets," Mr. Lipton said.

Mexico never tapped the previous credit line first approved in 2009.

Write to Ian Talley at ian.talley@dowjones.com