Simple, compound & super compound

Discussion in 'SP2' started by Sinead Mc Laughlin, Sep 13, 2016.

  1. Hi,

    I imagine this to be a simple answer but want to check as I couldn't find it in the notes.

    In April 2010 Q1 (iii) the question is

    "Over the past three years the company has declared regular bonuses of 1% p.a. using the simple approach. The actuary has determined that over the same period they could have declared 0.5% three years ago, 1% two years ago and 1.5% last year using the compound approach. (iii) Determine the benefit amount for a single premium policy written three years ago with a sum assured of 10,000, under both approaches. [2]"

    And the solution is:
    Simple Approach: = 10,000 + (1% * 10,000 * 3) = 10,300.00
    Compound approach: = 10,000 * (1 + 0.5%) * (1 + 1%) * (1 + 1.5%) = 10,302.76

    Are these derived from formulae? And what would the super compound answer be? Just not sure where the 3 comes from in the simple approach or why the compound adds 1 to each percentage?

    Thanks in advance.
     
  2. Mark Willder

    Mark Willder ActEd Tutor Staff Member

    Rather than memorising a formula, it's probably best to go back to first principles.

    A simple bonus is added to the sum assured only (ie it is not added to the attaching bonuses). So in the first year we add a bonus of 10,000 x 1% = 100. In the second year we add a bonus of 10,000 x 1% = 100. In the third year we add a bonus of 10,000 x 1% = 100. As the bonuses are the same every year, the solution just takes a shortcut and calculates the bonus as 3 lots of 100. So the total guarantee (sum assured plus bonuses) is 10,300.

    A compound bonus is added to the sum assured and the attaching bonuses. So in the first year we add a bonus (b) of 10,000 x 0.5% = 50, and the guarantee becomes SA x (1+b) = 10,050. In the second year we add a bonus of 10,050 x 1% = 100.5, and the guarantee becomes (SA+RB) x (1+b) = 10,050 x 1.01 = 10,150.5. In the third year we add a bonus of 10,150.5 x 1.5% = 152.26, and the guarantee becomes (SA+RB) x (1+b) = 10,150.5 x 1.015 = 10,302.76.

    Super compound bonuses are declared at different rates, eg 0.5% on sum assured and 1.5% on attaching bonuses. So in the first year we add a bonus (b) of 10,000 x 0.5% = 50, and the guarantee becomes 10,050. In the second year we add a bonus of 10,000 x 0.5% + 50 x 1.5% = 50.75, and the guarantee becomes 10,050 + 50.75 = 10,100.75. In the third year we add a bonus of 10,000 x 0.5% + 100.75 x 1.5= 51.51, and the guarantee becomes 10,100.75 + 51.51 = 10,152.26.

    If you would like more practice with these calculations, April 2015 also included lots of calculations of bonuses.

    Best wishes

    Mark
     
  3. Perfect that makes sense. Thanks very much Mark.

    Thanks,
    Sinead
     

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