This is helpful.
4. So is the release of reserves just the change in reserves between two successive time periods?
Yes - although we tend to use the phrase 'release of reserves' to refer to the situation when reserves are reducing over time.
5. Can the release of reserves over t and t+1 be negative?
Yes, in which case we would tend to refer to it as being an 'increase in reserves'.
Remember that (simplistically, for conventional business):
Profit = premiums + investment return - expenses - claims + release of reserves
OR (equivalently)
Profit = premiums + investment return - expenses - claims - increase in reserves
6. Given 1 and 2, does this mean the release of margins within the reserves (since this equals PVIF) is greater than the release of reserves (as this is a component of PVIF)?
No. By definition, must have margins < total reserves. The 'margins within reserves' means just the element of prudence within the reserves, as described in earlier answers.
7. How is Point 4 possible, particularly where the release of reserves are both a release of both the best estimate liability and the prudent margin - I thought this release would be larger than that of just the margins within the reserves?
Yes, it is.
6. Is this numerical example correct for release of reserves?
a) Solvency reseve in year t = BEL1 + Margin1 = 80 + 20.
b) Solvency Reserve in year t + 1 = BEL2 + Margin2 = 70 +15
c) Release of reserves = 100 - 85 = 15?
Yes
7. I'm having trouble comprehending "release of margins within the reserves", particularly what is meant by "remaining prudential margin"? In terms of the release of margins within Solvency reserves:
a) is it as simple as 20 - 15? I assume not and think I'm missing something here - could you give a numerical example for the release of margins within the Solvency reserves, where possible using the same numbers above?
Yes - the release of margins in this example would be 20-15 = 5. At the start of the year, we had to hold 20 in prudential margins, at the end of the year we have to hold only 15. So that means that we can release the no-longer-needed 5 - this doesn't need to be tied up into reserves anymore so could be released to shareholders. And so falls into the 'profit' calculation.
So let's think about the two different definitions of profit being released. Please note that these are simplistic statements, which I am using to help you get to grips with the over-riding concepts. There are other elements (for example, investment return earned on the margins in reserves), but it's not helpful to go into those: the high-level concepts are important rather than these sorts of details.
So, simplistically: profit being released over the time period equals:
release of prudential margins in reserves
OR
premiums + investment return - expenses - claims + release of reserves
In your example, our best estimate liab has reduced from 80 to 70. Let's assume that investment return on the assets backing the reserves = 0% to make things easier (and so we are also discounting reserves at 0%), and that experience = best estimate.
The reduction in liability of 10 at the end of the year implies that we must have {benefits + expenses - premiums} arising during the year = 10 [since reserves = PV{benefits + expenses - premiums}]. So, switching this round: {premiums - benefits - expenses} = -10.
So in this example:
Release of margins in reserves = 5
OR
Profit = P + I - E - C + Release of reserves = -10 + 15 = 5
In other words, the release of the BEL part of reserves pays for what is actually happening during the period in terms of meeting obligations to policyholders, and the prudential margins part isn't needed for that and so falls into profit.
[If we were allowing for investment returns and discounting, the investment return earned on the start year reserves offsets the discounting impact.]
Your questions sound more like SP2 than SA2 questions, so do make sure that you have thoroughly understood the basics that are covered in the SP2 material - this will be assumed knowledge for SA2, and it will be difficult to layer on the more advanced material if you don't have a really good foundation.