If they say internally at their board meetings and such that fossil fuels likely cause global warming, then the next day that are saying publicly that they don't, then they are legally fucked.
If I understand the baseless allegations correctly, the "fraud" is supposed to be that they didn't say anything to their board members.
Regardless, "likely" is an opinion and is speculation, not fact. They could not have known -- as a fact -- that there is a link between emissions and warming because that has never been established as a fact.
Indeed, the original draft of the IPCC's second report in 1995 said that a link hadn't been established connecting emissions to warming, in whole or in part.
Furthermore, the position ExxonMobil took publicly was that policy makers shouldn't make hasty decisions until more research could be done.
That was sound advice then. And given the enormous uncertainties that exist today, it remains sound advice.
Alarmists may disagree. But as I have said all along, having a different view than some alarmists is not evidence of "fraud."