The testimony phase of United Rentals’ lawsuit against Cerberus Capital Management ended December 19 after 24 hours. Delaware Court of Chancery Judge William Chandler III said he would rule promptly.

Last month, RAM Holdings and RAM acquisition, entities formed by Cerberus to acquire United Rentals for about $6.7 billion including debt, decided to back out of its $34.50-per-share agreement to acquire United even though there had been no “material adverse” change at United, which is typically required for a buyer to refuse to follow through on an acquisition. Instead, Cerberus cited uncertainty in the credit and financing markets. Even though none of the lenders had threatened to back out, Cerberus executives including its CEO Stephen Feinberg testified they still viewed the deal as risky and were nervous about the current financial environment.

Cerberus had agreed in the deal to pay a $100 million break-up fee. However, United Rentals contends a “specific performance” clause in the agreement requires Cerberus to go through with the purchase, and filed a lawsuit to force the acquisition. United Rentals’ stock price dropped by nearly a third when news of Cerberus’ decision to back out of the deal was leaked to the media. Cerberus insisted in the trial that its liability is limited to the agreed-upon $100 million fee.

The trial had been scheduled to begin Monday, but was postponed until Tuesday because of ongoing settlement talks. However, the talks ended Monday without an agreement, and the trial began on Tuesday.

Based in Greenwich, Conn., United Rentals is the rental industry’s largest company, No. 1 on the RER 100.