WeWork’s CEO is was in the spotlight this week after reports from The Wall Street Journal and The Information highlighted some unusual aspects of his leadership style.

Co-founder and Chief Executive Adam Neumann has reportedly bragged that he’s sold more than $100 million of WeWork’s shares, according to four unnamed sources who spoke to the Journal.

WeWork, a start-up that offers flexible shared workspaces for entrepreneurs, is privately held, making insider stock sales hard to track. But a CEO selling large amounts of share in a company is sometimes viewed as a lack of confidence by investors.

Neumann is considered a charismatic, upbeat leader who is known to work through the night, sources told the Journal. But his mettlesome negotiating style — combined with the high valuation of WeWork’s shares — has proven problematic to potential acquirees, The Information reported.

The company is backed by investors like Goldman Sachs and T.Rowe Price, according to third-party data EquityZen and Crunchbase. It raised $760 million this summer at a valuation of $20 billion, and turned around to raise another $4.4 billion from SoftBank a few months later.

Neumann has said WeWork is on pace for $1 billion a year in revenue and plans to go public at some point.

WeWork declined to comment.

For more, see the WSJ.com profile and The Information‘s piece.

— Reuters contributed to this report.