July 24 (Reuters) - Mexican cement maker Cemex said on Tuesday that creditors had so far agreed to swap debt holdings for $421 million of new high-yield notes as part of its plan to refinance a heavy debt burden.
The exchange offer, for up to $500 million of new 9.5 percent notes due in 2018, is part of a plan Cemex aims to conclude in the third quarter of this year to gain breathing room ahead of the maturing of $7.25 billion in debt in 2014.
The offer, which was launched early this month, ends on Aug. 20. The $421 million figure is as of July 19.
Cemex has been struggling with deep debt obligations for the past three years since it was swamped by the 2008 U.S. housing meltdown shortly after paying out some $16 billion to buy Australian peer Rinker.
Cemex last week reported its highest quarterly operating core profit in nearly three years on a pickup in its U.S. business.
Cemex shares closed down 1 percent on the New York Stock Exchange at $6.74 on Tuesday. Shares listed on Mexico's stock exchange dipped 0.65 percent to 9.19 pesos.
Reporting by Michael O'Boyle; Editing by Edwina Gibbs