Proxy advisory firm Glass Lewis said on Saturday it has urged Tesla, shareholders to reject a $56 billion pay package for Chief Executive Officer Elon Musk, which if passed would be the largest pay package for a CEO in corporate America.

The report cited reasons like the "excessive size" of the pay deal, the dilutive effect upon exercise and the concentration of ownership. It also mentioned Musk's "slate of extraordinarily time-consuming projects" which have expanded with his high-profile purchase of Twitter, now known as X.

The pay package was proposed by Tesla's board of directors, which has repeatedly come under fire for its close ties with the billionaire. The package has no salary or cash bonus and sets rewards based on Tesla's market value rising to as much as $650 billion over the 10 years from 2018. The company is currently valued at about $571.6 billion, according to LSEG data.

Also read: Tesla laying off more than 10% of staff globally as sales fall

In January, Judge Kathaleen McCormick of Delaware's Court of Chancery voided the original pay package. Musk then sought to move Tesla's state of incorporation to Texas from Delaware.

Glass Lewis also criticized the proposed move to Texas as offering "uncertain benefits and additional risk" to shareholders.

Tesla has urged shareholders to reaffirm their approval of the compensation.

In an interview this month, Tesla's board chair Robyn Denholm told the Financial Times that Musk deserves the pay package because the company hit ambitious targets for revenue and its stock price.

Musk became Tesla CEO in 2008. In recent years, he has helped improve results, taking the company to a $15 billion profit from a $2.2 billion loss in 2018 and seven times more vehicles have been produced, according to an online campaign website, Vote Tesla.

The proxy advisor also recommended shareholders vote against the reelection of board member Kimbal Musk, the billionaire's brother while former 21st Century Fox CEO James Murdoch re-election was recommended.