UPDATE 3-Mexico's Comerci offers equity stake to creditors

* Eyes convertible instrument in debt restructuring

* Company has until June 10 to strike deal

* Comerci shares slump as much as 14 percent

* No big changes to board after shareholders meeting (Adds background, details on meeting, updates stock quotes)

By Cyntia Barrera Diaz

MEXICO CITY, June 4 (Reuters) - Troubled retailer Comercial Mexicana said on Thursday that its latest debt restructuring proposal to creditors includes a possible equity stake.

Shares of the supermarket operator were down 3.32 percent to 7.56 pesos, recovering from a slump of 14 percent after the news was released.

The company defaulted on its debt in October after the global credit crisis sparked massive losses on extensive derivatives bets. Since then it has been trying to reach a deal without selling key assets or giving up ownership of the company.

In a filing with the Mexican stock exchange, the company known as as Comerci (COMEUBC.MX) said it had proposed paying undisclosed debt between six and eight years as well as asset sales over two to six years.

Comerci said debt convertible into shares was part of the proposal, but did not mention amounts, specific assets or other details.

A source close to the talks told Reuters last week that Comerci, controlled by Mexico's Gonzalez family, offered to repay $1.45 billion.

Creditors, which include JP Morgan Chase & Co (JPM.N), Barclays Plc (BARC.L), Goldman Sachs Group Inc (GS.N) and Bank of America Corp's (BAC.N) Merrill Lynch, claim they are owed more than $3 billion, mostly from soured derivatives bets.

Comerci's current offer would see the company repay $950 million from ongoing operations over seven years, according to the source. Another $500 million would be paid over six years and would be guaranteed by its Costco Wholesale (COST.O) venture and land reserves.

The source said creditors have been pushing for a stake in the company in lieu of part of the debt they are owed.

Mexican authorities are probing whether Comerci broke the law by not clearly disclosing its derivatives bets, which some experts say were unsuited to running a supermarket chain.

In an interview with Reuters last month, the head of Mexico's market regulator urged shareholders to sue companies that have suffered massive losses due to undisclosed derivatives bets.