The collective pension deficits of the UKs largest companies have increased by almost 50% since the beginning of this month, Towers Watson said today.

Total deficits for the FTSE 350 companies' pension funds are estimated to have grown from £62bn at the end of April to £92bn on May 16, according to the consultancy's tracking of scheme liabilities and assets.
Over three quarters of the increase in deficits was a result of growth in liabilities rather than assets losing their value. Between the end of April and May 16, the aggregate value of assets in the FTSE 350's defined benefit pension schemes fell from £542bn to £534bn, while schemes' liabilities, as measured for accounting purposes, are estimated to have increased from £604bn to £626bn.
John Ball, head of UK pensions at Towers Watson, said: 'The latest stage of the eurozone crisis has pushed down interest rates on high quality corporate bonds as well as gilts, as investors look for safe
havens. The lower these interest rates go, the bigger the pension liabilities in company accounts will look.'
So far, May has seen yields on corporate bonds sink to their lowest levels since they became a key reference point for companies calculating pension numbers to put in their accounts. The yields are used to convert the pension payments companies expect to make over several decades into a single liability figure.
Mr Ball added: 'Real interest rates are close to historic lows, especially now that inflation expectations have crept back up after softening earlier this month.
An increase in pension deficits of £30bn for FTSE 350 schemes in the space of a fortnight shows how easy it is for hard-earned profits to be offset by changes to the pension obligations on a company's balance sheet when markets are volatile.'