A commission set up by President Barack Obama in the wake of the worst accidental oil spill in American history will likely spare British oil firm BP from a charge of "gross negligence," opting instead to place blame on numerous companies involved in the rig's management, according to an official document released Thursday.

Shares in BP traded in British markets were on the rise Thursday morning thanks to the announcement, made in an advance chapter (PDF link) of the commission's full report, due out next week.

Calling the mismanagement "systemic" means the Department of Justice is unlikely to levy the most serious charge of "gross negligence," according to stockbroker Peter Hitchens of Panmure Gordon & Co., who spoke to British newspaper The Guardian.

"The national commission's report is another chink of light for BP," he was quoted as saying. "BP was named and held responsible in the report but it also said 'We can't solely blame BP.' It's hinting that there won't be a finding of gross negligence. What seems to be coming through is there was an unfortunate string of accidents which led to the disaster. BP had a near-death experience. But time is a great healer for BP it seems."

A charge of "gross negligence" would could have triggered criminal penalties for those involved in making decisions deemed negligent, and significantly higher financial liabilities for the company as a whole.

BP has recovered about two-thirds of the value its stocks lost since the spill's outset, the paper noted.

While it may escape the harshest possible penalties, the commission's text still places blame for the spill on BP -- along with Halliburton and Transocean.

Halliburton was responsible for cement casing around the well's bore hole, while Transocean was the rig's owner.

"[A] key question posed from the outset by this tragedy is, do we have a single company, BP, that blundered with fatal consequences, or a more pervasive problem of a complacent industry?" spill commission co-chairman William K. Reilly wrote. "Given the documented failings of both Transocean and Halliburton, both of which serve the off shore industry in virtually every ocean, I reluctantly conclude we have a system-wide problem."

Reilly formerly served as President George H.W. Bush's Environmental Protection Agency administrator, and spent several years as a consultant to the Texas Pacific Group, a private equity and investments firm with holdings that include energy utilities.

"The Commission’s findings only compound our sense of tragedy because we know now that the blowout of the Macondo well was avoidable," fellow spill commission co-chair Bob Graham added. "This disaster likely would not have happened had the companies involved been guided by an unrelenting commitment to safety first. And it likely would not have happened if the responsible governmental regulators had the capacity and will to demand world class safety standards. There is nothing that we can do to bring back the lives of the men we lost that day. But we can honor their memory by pledging to take steps necessary to avoid repeating the fatal practices of the past."

Graham is a former US Senator from Florida and a member of the Council on Foreign Relations.

The advance chapter also placed blame on a lack of federal regulations addressing pressure tests on cement well caps. The commission added that decisions which directly led to the blowout "clearly saved those companies significant time (and money)."

BP has one the worst records for safety and environmental protection among all the world's major oil producers. A recent investigation by ProPublica, based on internal documents a company insider leaked to the journalism outfit, found that "the company repeatedly disregarded safety and environmental rules," even in the face of its own internal probes warning that they risked a serious accident.