Activist investor Orange Capital LLC has taken a 5.3% stake in Calgary-based Bellatrix Exploration Ltd., according to regulatory filings.

New York-based Orange Capital is seeking board changes and management-succession planning among other initiatives, and wants the oil-and-natural-gas exploration company to explore strategic alternatives including a sale, the filing said.

Orange Capital has been building its position in the Bellatrix since July 2, and is the company’s largest shareholder slightly ahead of Fiera Capital Corp., which holds 5.2% , according to data compiled by Bloomberg.

Orange Capital’s position is valued at C$80.4 million ($73.2 million) based on Monday’s closing price of C$7.91 a share in Toronto.

Bellatrix has gained 1.3% this year for a market value of C$1.5 billion compared with a 15% rise in the Standard & Poor’s/TSX Energy Index.