Curious how the third largest energy deal, and 14th largest corporate take over in history, happened? The answer, courtesy of Reuters, is simple: all it took was a phone call. Sometimes it takes little more than five people to put together a $70 billion oil mega-merger. Shell's purchase of smaller rival BG, the third largest oil and gas merger ever, was prompted by a phone call on a Sunday in the middle of March between Shell's ambitious and acquisitive CEO Ben Van Beurden and BG's veteran chairman Andrew Gould. Explaining how the deal came together in under a month, Van Beurden said on Wednesday: "I called Andrew (Gould) up and we had a very good and constructive discussion about the idea and it very quickly seemed to make sense to both of us". That first call was made on March 15. "What has happened in the last month, apart from it being a logical deal it has also become a very compelling deal from a value perspective," Van Beurden said. The rest is history. The winners from this blitzdeal, however, will not be shareholders. We reported why earlier, citing BMO: From our valuation perspective for RDS the BG deal is significantly dilutive, both from a multiple and asset value perspective. Shell is paying a P/E of 66.6x for BG at the acquisition price, although RDSA was trading at only a 12.1x 2016 multiple pre-deal. On an EIT/DACF basis, Shell's 2016 multiple is 6.2x, whilst it will be paying 11.7x for BG. RDS would also be paying a premium of 26% of BG's asset value, we estimate, even after the synergies are accounted for. We estimate that our PDS NAV is diluted by 8% as a result of this the deal. For these reasons we think the market will be sceptical about this deal and we believe Shell will have to work very hard to convince shareholders that the strategic benefits outweigh the premium offered. Basically, a deal of desperation, meant to give a few more non-GAAP quarters of breathing room before shareholders demanded Mr. Van Beurden's head on a metaphorical (one can't be too careful with ISIS running around these days) silver platter. Still, one group will profit handsomely from the deal. The bankers: Helping to make it happen were three bankers who have advised on some of the oil industry's biggest takeovers -- Alastair Maxwell from Goldman Sachs, Julian Mylchreest from Bank of America Merrill Lynch and former Morgan Stanley star deal maker Simon Robey, now with his own boutique firm Robey Warshaw. * * * Less than two months ago, Goldman's Maxwell played down the prospect of mega-mergers as oil majors were more focused on cost cutting and maintaining dividends. By March, he was advising BG on the deal together with Robey Warshaw. BAML is the sole adviser to Shell. When historicans look back on the annals of impromtpu deal decisions, this will fall somewhere just shy of Warren Buffett's bathtub investment in Bank of America.