THE impact of what initially seemed a human and environmental disaster, but not a business disaster has taken everyone, including BP, by surprise.

Since 20 April when the Macondo Well tragedy occurred BP has seen $75bn wiped off its market capitalisation – an absolute market value loss of 39 per cent and unprecedented in corporate history for a single event. Relative to the Bloomberg global oil and gas index BP has underperformed by $37bn – almost double the ballpark $20bn figure analysts estimate it will cost BP to clean up the spill and settle claims. That is quite a gap.

While chief executive’s Tony Hayward’s comments that the spill, leaking up to 19,000 barrels of oil into the Gulf of Mexico a day is “tiny” were disastrous in public relations terms, in terms of the overall business he has a point.

BP had assets and revenues of almost £163bn last year and net profits of £12bn. This may be one of the worst environmental disasters in history, but it is a one-off event which ultimately will not alter the long term earnings power of BP.

Investors are clearly afraid that BP will be forced to cut or suspend its dividend in a bid to appease Obama’s administration. A rare event that last happened 18 years ago and one that is unlikely to repeated. A belief reflected in the fact that most analyst houses continue to advise investors to “buy.”

With BP’s share price at 429.75p the shares are almost at parity with its net book value per share.

As JP Morgan’s Fred Lucas says “At times like this, we can but encourage investors to stay in touch with the facts, however negative sentiment has become.”