两者都与公司的pension养老金计划有关。

projected benefit obligations简称PBO，指预计给付义务。其英文释义如下：

A projected benefit obligation (PBO) is the estimated present value of an employee's pension, under the assumption that the employee continues to work for the employer. This information is needed by the employer to account for a pension liability, but is only needed when the pension is of the defined benefit variety.

accumulated benefit obligations简称ABO，指累积给付义务。其英文释义如下：

Accumulated benefit obligation (ABO) is the approximate amount of a company's pension plan liability at a single point in time.The assumption for the accumulated benefit obligation (ABO) is that the pension plan will be terminated immediately, meaning that there will be no more future salary increases. Accumulated benefit obligation (ABO) is equal to the present value of the future amount that a pension plan expects to pay an individual during their retirement.

ABO与PBO均指预期未来要支付的养老金的精算现值。

两者的区别在于：

ABO是以现有的工资水平为基础计算的，PBO是以未来的工资水平为基础计算的。大多数人认为，ABO更符合负债定义，因为负债的存在只能基于过去已发生的事项而不是未来事项，ABO以现有的工资水平为基础，所提供的会计信息更具有可靠性；但也有人认为，ABO以现有的工资水平计算虽然减少了不确定性，但无法真实地反映出企业未来的养老金给付义务，缺乏相关性。在持续经营的会计假设下，建立在未来工资水平的基础之上的PBO是企业未来最可能履行的义务，它直接影响着企业未来的现金流量，同时也更具有不确定性。在约定给付养老金计划下，主要运用PBO计算养老金成本与负债，ABO只是在计算最小负债（the minimum liability）时用到。

以下为相关双语示例，供参考：

The estimates and assumptions that have a significant effect on the carrying amounts of assets and

liabilities include those related to investment properties, impairment of assets, income taxes and projected benefit obligations. 

对资产及负债账面值有重要影响的估算及假设，包括与投资物业、资产减值、所得税及预计给付义务相关的估算及假设。 

Benefits at valuation date which are called Accumulated Post-Retirement Benefit Obligation (APBO), equal the benefits at retirement prorated for service at the valuation date. 

估值日的福利称作累积退休后给付义务（APBO），相当于退休时截至估值之日的服务所应得的那部分福利。