Shares in newspaper publisher Johnston Press soared 12 per cent on Wednesday after it announced the findings of a study that could more than halve its pension deficit of £90 million to £37m.

The London-based company, which produces some 220 newspaper local and regional newspaper titles including the Scotsman, said it would not publish the actuarial assumptions that informed the study into the company’s pension scheme liabilities until late next month, when its preliminary annual results are published.

A statement made to the London Stock Exchange said that the implementation of International Accounting Standard (IAS) 19 would reduce the media group’s pension deficit by £50m.

The statement also said that new rules drawn up by trustees would allow the company “to participate in any surplus when the scheme closes” with the result that the application of IFRIC 14 (an international pension accounting standard which resulted in an additional liability of £3m in January 2015) “will not be required”.

A source in the actuarial profession told The Herald that, while Johnston’s claim to be able to reduce its pension liabilities by such a massive amount through the “technical application of accounting standards” might “raise eyebrows” such “step changes are not unheard of”.

Ian Gordon, a pensions lawyer with Pinsent Masons said it was possible that Johnston Press had revised its mortality assumptions on how long members of its pension scheme were likely to live.

“This doesn’t mean that anything fundamental has changed,” he said. “The pension liabilities of the company will not have reduced: what has changed is the way in which those liabilities have been valued."

Johnston Press’s pension scheme deficit as well as its debt pile have been an albatross around the company’s neck since the financial crisis got underway.

Prior to the economic downturn, the group bought many of its titles through a debt-fuelled acquisition strategy that current chief executive Ashley Highfield has successfully reduced. The company’s most recent full year accounts showed net debt falling from £302m at the end of 2013 to £184.6m at the end of 2014.

Last month, the regional publisher said it planned to sell off some of its titles to rivals in order to focus on “gems” for the future as part of a strategy to focus on wealthier readers with “more disposable income”.

Scotland on Sunday and 15 other Scottish regional local papers were categorised as “sub-core” titles that might be disposed of in the future as the company focuses on digital growth and paying down debt. UK-wide the company has identified 59 titles that it could sell.

Johnston Press last month announced a further round of job cuts in a bid to reduce costs following a decline in advertising revenue. The company has reduced around 1,000 editorial jobs across the group since 2009.

Shares in the company closed up 4.5p on Wednesday at 41p.