Activist investor Fir Tree Partners on Feb. 4 called on oil producer Halcón Resources Corp. (NYSE: HK) to appoint two independent directors to its board, threatening a proxy fight at the next shareholder meeting if it fails to do so or fails to put itself up for sale.

Fir Tree, in a letter to the Halcón board of directors, accused Halcón of "excessive" spending, pointing to executive compensation that outpaced its peers and private plane use by CEO Floyd Wilson, which it said was on track in the third quarter to top $1 million in 2018.

Halcón did not immediately respond to a request for comment. A representative for Fir Tree Partners did not respond to a request for comment.

Halcón was hard hit by the 2014 crash in oil prices and emerged from bankruptcy restructuring in 2016. While U.S. crude prices rebounded in the first half of 2018, the producer posted an $81.8 million loss in its third quarter and a $100.7 million loss for the nine-month period.

Fir Tree, which owns about 7.2% of Halcón, in October called for a sale of the company. On Feb. 4, it said that if Halcón does not cut expenses and appoint new board members, Fir Tree may run a proxy contest at the next annual general meeting to replace its entire board.

Since October, Halcón shares have fallen by 56%. They were trading at around $1.75 per share on Feb. 4.

Although Halcón's assets are in the Permian Basin, the largest and fastest growing oilfield in the U.S., Wall Street values its land at less than $5,000 an acre, compared with peers whose land is valued above $20,000 an acre, Fir Tree said in its letter.

"The unfortunate reality for Halcón is that it is an over-levered and sub-scale operator that cannot organically grow out of its problems in the current [or most any] commodity environment," Fir Tree said.

Fir Tree also took issue with CEO Wilson's compensation package, which it said was valued at $24 million when the company emerged from bankruptcy in 2016 and roughly $7 million in 2017, a year in which its stock fell by more than 50%.