Rathbone Brothers, a centuries-old wealth manager, carried out a surprise rights issue Thursday as it seeks to plug a pension deficit gap that has expanded markedly since Britain's Brexit vote in June. 

The London based firm is the latest to have reported a surging pension deficit since the referendum, which prompted the Bank of England to cut the U.K.'s benchmark interest rate to a new record low of 0.25%.

The news also came closely on the heels of a report issued by management consultancy, Mercer, which projected London's FTSE 350 companies could be left with a £2 billion bill in 2017 if they are to offset the increased cost of funding employee pension schemes. 

Rathbone raised £38 million ($47 million) from a placing with institutional investors after its pension deficit widened to £58.4 million in the three months to the end of September from £4.5 million at the end of 2015, creating a gap in the firm's regulatory capital buffer.

Management did not disclose the size of the regulatory capital hole but attributed the wider pension deficit to a sharp fall in U.K. corporate bond yields during the year as the BoE added those assets to its quantitative easing program. 

The group issued 2.2 million shares at a price of 1,710.0 pence each, equating to a discount of around 3% from Wednesday's closing price, raising an amount equal to 4.6% of its share capital. It had a market capitalisation of £868 million before the placing on Thursday.

"We concluded we needed to take the actions we have announced today ... the capital raising will enable us to progress these actions and support our continued future growth," said CEO Philip Howell, whose team also warned in a third quarter trading update that it is possible 'further actions' will be required in the future.

Rathbone Brothers stock was up by 2.2% mid-way through afternoon trading in London, at 1,801.0 pence, although it is down by more than 18% for the year-to-date.

But the wealth manager is just the latest to fall victim to Britain's hidden pension crisis, which has been made worse by the fall in bond yields since August, when the Bank of England cut interest rates and unveiled a mammoth stimulus package in order to stave off an anticipated downturn of the economy.

Tesco (TSCDY) , Britain's largest employer and one of the world's largest retailers, reported its pension deficit had almost doubled during the six months to the end of August, rising to £5.9 billion from £3.2 billion.

Furthermore, a report issued Thursday by management consultants at Mercer projected that the U.K.'s FTSE 350 companies could see their collective earnings fall by as much as £2 billion in 2017, due to widening pension deficits across the board.

"The impact of over £2 billion on profits is material compared with pre-tax profits of FTSE 350 companies of £84 billion in 2015," said Warren Singer, head of pension accounting at Mercer.  

Mercer research shows that, overall, FTSE 350 companies had a collective pension deficit of £119 billion at the end of June. This is while, according to a post-Brexit report from PwC, the combined pension deficit for all U.K. firms is around £710 billion. 

Shares of Rathbone Brothers may have risen in the wake of Thursday's announcement, and those of Tesco might be up as well since it unveiled first half results earlier in the month, but pension deficits are already becoming a deal breaker for some investors.

In August one of the U.K.'s most popular fund managers, Neil Woodford, made headlines when he sold his stake in BAE Systems (BAESY)  

Among the reasons cited for the decision were the barriers to investment and growth thrown up by a rising pension deficit at the weapons manufacturer.