Prominent shale investor Dan Wilks on Jan. 19 reported a 7.5% active stake in troubled oilfield services firm ProPetro Holding Corp. through an investment vehicle, saying he may choose to push the company for a sale or other alternatives.

Dan Wilks and his brother Farris Wilks made their fortune on the shale boom through a company they founded called Frac Tech Services, which provided trucks to frackers. They sold their majority stake in the company in 2011 for $3.2 billion to a consortium led by Temasek, a Singapore sovereign fund.

Over the past few years, the brothers have been acquiring stakes in hard-hit services firms across North America and most recently engaged in a lengthy takeover battle for Canada's Calfrac Well Services Ltd.

Dan Wilks first reported a near 10% passive stake in ProPetro in April, a month after the company's CEO stepped down in the aftermath of investigations about its financial reporting and controls.

The COVID-19 pandemic and the resulting slump in oil prices piled on to ProPetro's woes and its shares slumped more than 30% through 2020.

THRC Holdings LP, Dan Wilks' investment vehicle, filed the change in his holdings with the U.S. Securities and Exchange Commission on Jan. 19 and said the investor could engage in talks with the company's board or other shareholders about possible changes.

The possible changes could be related to the oilfield service provider's capital allocation, ownership structure and could include mergers or an outright sale, THRC's filing said.

ProPetro declined to comment on the news.