"Preponderance of Evidence" Standard Deems Lost Profits Recoverable

For many years, the majority of state and federal courts have held that the recovery of lost profits is governed by a "reasonable certainty" standard, at least in the first instance of determining whether the "fact" of lost profits is established, as opposed to the second level of the question, i.e., determining the amount of lost profits to award. This has prompted debate as to how much evidence is required to establish "reasonable certainty"? Is it something more than a preponderance of evidence? Does it approach "beyond a reasonable doubt"?