United Rentals Monday filed a lawsuit against Cerberus Capital Management’s RAM Holdings and RAM Acquisition Corp. to force the private equity group to go through with its agreed-upon acquisition of the Greenwich, Conn.-based rental company.

The lawsuit, filed in the Delaware Court of Chancery, contends that Cerberus violated the merger agreement and should not be able to avoid the agreed-upon transaction by paying a break-up fee. The lawsuit contends that the “specific performance” clause in the merger agreement gives United the right to compel “consummation of the merger in the present situation.”

RAM Holdings, the Cerberus acquisition vehicle for the deal, said its liability is limited to the $100 million break-up fee, which it has not contested. Cerberus also has said it is willing to lower the price of its offer, an option United Rentals does not appear willing to accept.

United Rentals said, in a statement, that Cerberus’ repudiation of the deal “is nothing more than a naked ploy to extract a lower price at the expense of United Rentals' shareholders.” The company added that "irreparable damage would occur in the event that any of the provisions of the agreement were not performed in accordance with their specific terms or were otherwise breached," and that Cerberus’ actions give United Rentals the right to compel consummation of the merger in the present situation.

Cerberus has admitted that there is no financing barrier to completing the merger, as RAM has binding commitment letters from its financing sources to provide financing for the transaction. United Rentals believes that the financing sources stand ready to fulfill their contractual obligations.

The lawsuit also contends that the Cerberus acquisition vehicles sought to further its scheme to buy United Rentals for less by taking advantage of the dramatic stock price drop that occurred after their intention to walk away from their obligation to consummate the merger was leaked to a news organization.

After the news of Cerberus’ decision to back out of the agreement was reported, the United Rentals stock price fell $10.24 to close at $23.50. At the close of trading Monday, United Rentals share was $22.50.

Unlike other private equity deals that have broken apart in recent months, Cerberus is not citing a “material adverse change” in the business as a reason for backing out, rather citing uncertainty in the credit and financing markets.

United Rentals’ third quarter results were solid and the company said its new strategic plan, including a cost-reduction effort, will help the company maintain its strong performance.

United Rentals is the equipment rental industry’s largest company, No. 1 on the RER 100.