The ability to retire from work at a certain age is a fundamental human right, and the funding for that retirement is a Natural Monopoly. The People shall manage a pension system to provide for the support of retired persons at the Standard Income level starting at the age where an individual has lived an estimated 80% of their lives.
Economies of scale require that the pension system be administered globally, to be derived from global revenues. Allowing corporations, unions, or other organizations to manage pensions is fundamentally unfair because the amount an individual receives is highly dependent on accidents of circumstance.
The eligibility age for pension will be determined on an individual basis such that the individual will be able to spend 20% of their estimated life span be spent in retirement if they so choose (if you’re wondering if this estimate can actually be reliably made, ask an insurance actuary: It’s a business and a science). There should be no forced retirement age, however, and the pension must be paid starting at this age regardless of work status.
Pensions will be the same for all individuals, the Standard Income defined for the Locality in which the individual worked (weighted averaged if there are multiple). Individuals should be expected to supplement this amount with individual savings or other assets, or by continuing to work if they prefer a higher standard of living. This design has the additional benefit that pensioners will be highly motivated to ensure that the Standard Income level is set correctly for each Locality, and will play an active role in both local and global governments where their combined experience will be a great asset to The People.
Note that there may be dragons here too: Many private and union pensions are underfunded and/or have overpromised benefits, some of them criminally so, especially when declining populations (which are inevitable under any scenario) are taken into account. When these assets are folded into the Globality for distribution, land-lease rates for a new Locality will need to be adjusted such that this debt can eventually be repaid.