FILE PHOTO: SpaceX founder Elon Musk smiles at a press conference following the first launch of a SpaceX Falcon Heavy rocket at the Kennedy Space Center in Cape Canaveral, Florida, U.S., February 6, 2018. REUTERS/Joe Skipper

(Reuters) - Influential proxy advisory firm Glass Lewis said Tesla Inc TSLA.O shareholders should vote against a proposal to grant Chief Executive Officer Elon Musk performance-based stock options worth about $2.62 billion.

If Musk earned the full grant, he would own 28.3 percent of the company, although Tesla’s proxy statement showed that his ownership was expected to be lesser, Glass Lewis said in a report dated Feb. 28.

“The cost of the grant is staggering relative to executive compensation levels among public companies worldwide,” Glass Lewis said. The grant would dilute other investors and prove too costly, it added.

The proxy firm values the award at about $3.7 billion, based on a different valuation model it used.

The award is seen as an effort by Tesla to reassure investors that Musk will continue to helm the electric car maker in the long term and that his interests will align with those of Tesla stockholders, Glass Lewis said.

Some analysts have questioned whether Musk’s other interests, from space exploration to tunnel boring technology, are a distraction at what is seen as a critical time for Tesla.

Musk has touted 2018 as an important year in the Silicon Valley company’s history, highlighting plans to ramp up production of its Model 3 sedan that has faced numerous production delays over the past year.

Tesla declined to comment on the Glass Lewis report.