HOUSTON - XTO Energy Inc's Chairman Bob Simpson may receive around $70 million in compensation after the company's deal with Exxon Mobil Corp closes, according to regulatory filings.

Simpson would have been due a $120 million bonus if the U.S. natural gas company he founded signed a deal by June 1, or a $60 million bonus if the deal was signed by Dec 1. But those amounts reset to zero after Dec. 1, according to a footnote in the company's April proxy filing with the U.S. Securities and Exchange Commission.

Exxon Mobil Corp agreed to buy U.S. natural gas company XTO on Monday in a stock deal valued at about $30 billion.

Excluding the bonus, Simpson is due roughly $50.7 million in compensation under the change of control clause in his employment agreement, according to the proxy statement.

The executive's employment pact was also modified in September to say he will receive an amount in cash equal to three times the value of about 150,000 XTO shares granted by company in January if the company is acquired.

The value of those shares will ultimately be based on the closing price when the change in control occurs, according to the regulatory filings. Based on the last closing price before the deal was announced, those shares are worth more than $18 million.

Officials at XTO did not immediately respond to a question about Simpson's compensation. (Reporting by Anna Driver in Houston and Mike Erman in New York; editing by Andre Grenon)