Hi 2mc, You said The crucial calculation is the true average cost which is based on LIFO. Do you mean something like this? (Don Carson asked me) This is part of my reply to him.
(Maybe, got to learn more about it. This may be what he is doing
Now let's say the price jumps to $15, your stocks are now worth $510, and he wants to sell some. I thank he is using $8.8/$15 to get .58 . At this point I am not sure how much he is selling of the stock value, it could be .58 or (1-.58 =.42), lets use .42. $510*.42= $214. $214/$15= 14 shares(rounded). He says he recalculates a new average cost.
The new average cost is $11.5. Not sure if this is what he is doing or not.)
You said Value can never fall greater than 100% below cost but value can be any percentage above cost. So, there is a mathematical way of muting this disparity or of evening the percentages out. You probably learned this formula in High School algebra. Anyway, it is this that I use for the factor. Could you post the mathematical formula, it has been a while since I hit the school books, thinks.
Concerning Synchrovest it does not use average buying price. My understanding of average buying price is this, you add up the prices that you bought stock at and divided by the number of prices. Synchrovest does not do this. It does use average cost. My understanding of average cost is, add up total cost and divide by total number of stocks. This is what Synchrovest does. Note: in my spread sheet commissions are not included in total cost. But I feel they should be.
Come see me at Systematic Investing group #board-966 lets talk formula plans.
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