The wealth management company's survey, which polled almost 1,300 UK adults, found the main reasons for losing track of their savings are that individuals "never kept an interest", lost paperwork or forgot to notify providers of address changes.
Of those who had moved home, 13 per cent admitted they had never notified their pension providers of their change of address and a further 12 per cent confessed they were unsure.
When asked how they would find a lost pension, most savers (32 per cent) would contact their previous employer, but a fifth of respondents (20 per cent) said they had no idea how to find their cash again.
Andy James, head of retirement planning at Tilney, said: "It is all too easy to lose track of a pension due to a combination of inertia, disinterest fuelled by excessive technical jargon and absent minded administration.
"Tracking down missing workplace pensions can be particularly problematic where a previous employer from many years past has been acquired or gone bust, moved or re-branded.
"But it really is vital to track down these pots of assets and to determine whether they remain fit for purpose."
Tilney's research concluded the average person has worked for 5.8 employers by the time they are over 55 but this is set to increase significantly, as 18 to 34-year-olds have already had, on average, over four jobs and even small businesses are now required by law to auto-enrol new staff into a workplace pension.
Projections by the Department of Work & Pensions (DWP) estimate the average person will have 11 employers over their working lives.
One solution to the problem of losing track of pensions would be to consolidate these scattered pots into a single plan, Tilney stated.
But most individuals (72 per cent) have never consolidated plans with the main reason being they had never thought about it (23 per cent) and didn't know how to (20 per cent).
The research also highlighted how disengaged much of the British public were with their retirement plans, despite the importance these assets have in financing their future lifestyles.
One in five respondents admitted they had never checked their current workplace pension, while 13 per cent had no idea what their pension was worth, and a quarter of those asked were unable to differentiate whether their current pension was a defined contribution (DC) or defined benefit (DB) scheme.
Furthermore, 47 per cent of men and 62 per cent of women with pension plans admitted they didn't know where their pension was invested, and 38 per cent didn't know which company was managing their current plan.
Some 62 per cent had no idea what the annual pension allowance was, while 67 per cent admitted they found the language of pensions confusing – especially women (75 per cent).
Mr James said people should start by using the government's Pensions Tracing Service if they needed to track down a missing pension.
He said: "The DWP is also working with the pensions industry, regulators and technology firms with a view to launching pensions dashboards - the aim of which is to provide a consolidated view of all pensions owned by a saver alongside the state pension.
"Such a development is urgently needed, however there are serious concerns about whether this will be able to be achieved by the targeted launch date of April 2019. The DWP has fallen behind schedule in publishing a feasibility study."
Government officials had said previously that this study would be published in March.
Paul Gibson, managing director of Granite Financial Planning, said he often has clients who had several pensions, and many have lost track of some of them, "particularly where providers have re-branded or been taken over".
He said: "I have a client who was recently reunited with a pension he did not even now he had worth over £48,000.
"Consolidation makes sense for many clients but advice should be sought from an independent financial planner.”
maria.espadinha@ft.com
