With Elliott Management investing a sizable stake of more than $1 billion in Twitter (TWTR), the hedge fund is looking to make some changes at the social media company, which could reportedly include ousting co-founder and CEO, Jack Dorsey.

According to Bloomberg, executives from Elliott Management met with Twitter representatives, where Dorsey was notably absent and became the main topic of conversation between the two companies.

Elliott is looking for Twitter to have a full-time CEO as Dorsey, who has a net worth of $6.01 billion, according to the Bloomberg Billionaires Index, splits his time between Twitter and Square Inc. But the billionaire has more than 85% of his wealth residing in mobile payment system Square, where he spends half of his time as CEO, Bloomberg reported.

Elliott has reportedly shown concern for Dorsey’s absence at Twitter, including time away to work in Africa for as much as six months a year, saying the progress of Twitter is slowed, causing the company to be undervalued. Elliott reportedly thinks that Twitter needs a CEO that will focus solely on the company as new users and advertisers come in numbers to the social media platform.

Dorsey co-founded Twitter in 2006, and Elliott’s strategy of change is not the first time that Dorsey’s role has been questioned. Shares of Twitter stock have fallen 6.2% since Dorsey returned as CEO of the company in July 2015 after taking a break from the role, while social media competitor Facebook has seen its shares gain 121% during the same timeframe, the news outlet said.

Shares of Twitter stock were up 8.49% as of 12:10 p.m. EST on Monday.

Jack Dorsey
Twitter CEO Jack Dorsey. Getty