The most expensive U.S. shale acquisition of the year may be threatened by an investor’s concerns over one of the company’s midstream components.

Hedge fund Jana Partners LLC, one of the country’s leading producers of headaches for boards of directors, fired off letters to the board of EQT Corp. accusing management of overpaying in its $6.7 billion (with absorption of $1.5 billion of debt) offer for Northeast gas producer Rice Energy Inc.

Jana disclosed that it had purchased a 5.8% stake in EQT. Its founder and managing partner, Barry Rosenstein, wrote that EQT’s shares were undervalued and that the company could save as much as $4.5 billion if it separated its pipeline assets instead.

“...Our continuing analysis of the $2.5 billion in original synergies, which we noted in our first letter to the company, appear to have been overstated by as much as $1.3 billion, along with management’s own comments about these synergies, have raised even more questions about their credibility,” Rosenstein wrote in a letter to the board.

The deal would vault EQT into the top position among U.S. natural gas producers and continue an acquisition trend away from the oil-centric Permian Basin toward gas-centric plays like the Marcellus, Utica and Haynesville. Ironically, the transaction would actually reduce anticipated volume growth out of the Marcellus, Ethan Bellamy of Baird Equity Research told Hart Energy in June. Steve Schlotterbeck, CEO of EQT, said in a conference call that the shale revolution’s evolution into a new phase necessitated slower growth.

In an interview with Hart Energy’s Leslie Haines, Schlotterbeck belied few concerns that the acquisition could be completed in 2017.

“We probably have about five months before closing at year-end, so that will be a big, big task,” he said. “However, because of the similar nature of the companies and the direct overlap of our operating areas, we’re hoping to make the transition as seamless as possible. That said, integrating the IT and accounting systems is always a major effort that will take some time on our part.”

Joseph Markman can be reached at jmarkman@hartenergy.com or 713-260-5208.