Exxon Mobil Corp's chief executive earned 20 percent more in 2011 than the year before, and the company said it saw no reason to change its pay practices, as had been urged by some investors.

Chief Executive Rex Tillerson received $34.9 million in total compensation, up from $29 million in 2010, Exxon said in a proxy statement filed with regulators on Thursday.

The CEO of U.S. rival Chevron Corp, John Watson, collected a total of $24.7 million in 2011, his second year in the job. That was a 52 percent increase from $16.3 million in 2010, according to Chevron's proxy, also out on Thursday.

Tillerson's pay package included stock awards valued at $17.9 million and bonus and salary totaling $6.8 million. Watson received $5.6 million in salary and non-equity incentives, and the rest in stock, options, pension and deferred compensation.

Exxon's board of directors bases its compensation decisions on long-term financial targets, among other factors.

Last year, proxy firm ISS criticized Exxon's compensation practices, and argued that the company's shareholder returns did not justify executives' pay packages. Returns, ISS said, were inflated by higher crude oil prices.

In this latest proxy statement, Exxon said that it had spoken with a number of shareholders about its compensation practices following a non-binding say on pay proposal that won approval with 67 percent of shareholder votes.

We believe that applying a short-term, formula-based approach to ExxonMobil's compensation program would undermine the uniquely long-term requirements of our proven business strategy, the company said in the filing, with the U.S. Securities and Exchange Commission.

In this year's proxy statement, Exxon used a chart to illustrate that its shareholder returns had outperformed those of its peers and the Standard & Poor's 500 over a 20-year period.

Exxon said its conversations with shareholders included consideration of the use of formula-based pay tied to shorter-term metrics such as one- and three-year total shareholder returns, a practice that ISS urged the oil company to adopt.

Shareholder proposals on the proxy related to hydraulic fracturing, greenhouse gas emissions and splitting the job of chairman and chief executive.

The annual meetings of both Exxon and Chevron are scheduled for May 30.

Both companies will face votes on resolutions related to the oil and gas production practice of hydraulic fracturing. Similar resolutions last year won support from 28 percent of Exxon shareholders and 40 percent of Chevron's shareholders.

(Reporting By Anna Driver in Houston and Braden Reddall in San Francisco; Editing by Steve Orlofsky)