(Adds details on hedges, IMF credit line)
MEXICO CITY, Nov 13 (Reuters) - Mexico has finished its 2015 oil hedging program, paying more than 40 percent more for this year to protect revenue from crude exports used to finance a third of the government's budget, the finance ministry said on Thursday.
Finance Minister Luis Videgaray told reporters that Mexico purchased put options between September and November to guarantee an average oil price of $76.40 per barrel for next year's exports, below the forecast price in the country's 2015 budget.
Since June, benchmark oil prices have fallen more than 25 percent because of a supply glut and slower economic growth worldwide. Prices for heavy Mexican crude MEX-OSP dropped to a four-year low on Thursday.
Videgaray said that the hedging program, combined with 7.9 billion pesos ($580 million) from the country's $33.6 billion rainy day oil fund, will ensure that the government can fund next year's budget even if oil prices slump further.
"Today we already have covered 100 percent of the price in the income law," Videgaray said.
Mexican lawmakers last month passed the income plan for the 2015 budget using a forecast for an average oil price of $79 per barrel.
The oil hedging program by Mexico, considered the largest operation by a nation in commodities markets, is designed to protect vital crude export revenue from market volatility.
The market slump forced Mexican lawmakers to trim the 2015 budget and drove up the price of the options that the government bought, to $773 million for 2015 from $543 million for the 2014 hedge, Videgaray said.
Videgaray said no further trades were needed to back up next year's budget after the government had covered average exports of 228 million barrels, up from 215 million in the 2014 hedge.
Marco Oviedo, an analyst at Barclays, noted that lower-than-expected crude output could still crimp the 2015 budget.
Production has flagged this year at Mexico's state-run oil company Pemex, hurting public finances even though the drop in revenue was offset by higher tax collections. (U.S. $1 = 13.6085 Mexican peso) (Reporting by Luis Rojas Mena and Tomas Sarmiento; Writing by Michael O'Boyle; Editing by Simon Gardner and Steve Orlofsky)