While executives and their advisers from both companies were wooing investors in New York, Boston and California, further shots were being fired in the UK. Both sides are targeting key institutional shareholders in the run- up to Friday's close, though the signs are that investors are still undecided.
One New York fund manager who met both sides yesterday said: 'They do a great job at trashing each other. You've got to sift through a lot of rubbish to get to the bottom of this one. I can't yet say which way I'm going to vote. But then, no one has to make up their mind yet.'
Enterprise's latest document to UK shareholders concentrated on the rising oil price, arguing that a combined group is just as likely to benefit from an increase as Lasmo alone.
Graham Hearne, chairman and chief executive of Enterprise, said the combined company would be more resilient to any fall in oil prices than Lasmo on its own.
Rudolph Agnew, Lasmo's chairman, said: 'We no longer hear much about claimed benefits of size or synergy. Having attacked our oil price assumptions as optimistic, it has shifted ground again by now attempting to make a virtue for the offer out of rising oil prices.'
He added: 'The truth is that Enterprise is nakedly seeking to buy Lasmo on the cheap.'
Analysts see the decision of Phillips & Drew Fund Management, which owns about 16 per cent of Lasmo and is due to be visited by Lasmo directors on Wednesday, and US shareholders, who own about 20 per cent, as crucial to the outcome of the offer.