Three months after its initial bid, Energy Capital Partners has increased its offer for nuclear waste management firm EnergySolutions from US$3.75 per share to US$4.15 per share.

The new offer from the private equity firm has an 11% add on premium to the closing share price of the Salt Lake City based waste management company of US$3.73.

The company, according to FactSet, has 91.1 million outstanding shares. The largest shareholder is Carlson Capital LP, who originally opposed the buyout plan back in January. It has revised its position, saying that it will now vote for the approval of the deal because of the new terms.

According to Tyler Reeder, partner at Energy Capital, "We have increased the purchase price principally to gain broader support for shareholders for this transaction."

The deal still requires Utah state regulatory approval aa well as the Nuclear Regulatory Commission approval. The new offer is set to be  approved by shareholders of EnergySolutions during its April 26 special meeting.