Saul,
I’ve set up some spreadsheets to keep track of my portfolios. I’ve adopted your method of setting a unity factor at the beginning year value and tracking growth (or if things go bad, shrinkage) by multiplying present value by the factor.
I understand how to adjust the factor based on the introduction or withdrawal of cash. I assume the same method applies to the introduction or withdrawal of equities, but this does introduce a new wrinkle.
I’ve got four portfolios. I currently have an advantageous tax situation which I am using to migrate my traditional IRA to my Roth IRA. But here’s the rub. As I merge the portfolios I’m wondering how I account for the past performance of the trad IRA which will be eliminated at the completion of this action.
The two IRA portfolios are significantly different in both size and composition with the Roth being about 4x larger in value and holding 19 companies while the trad holds 5 positions. The two portfolios only have two positions in common.
I’ve got two notions on how to do this: 1) Just take a snap-shot of closing price when the stock moves and treat it as a cash infusion (this is the amount I’ll have to pay taxes on). Forget about past performance. 2) Add the two beginning year valuations together and calculate a new factor based on this amount, then move the equities from the trad IRA to the Roth and pretend like they were there all along. Whatever growth or shrinkage they’ve experienced will just factor into the overall performance of the Roth.
The second approach seems like it appropriately accounts for the performance of the trad IRA. But I’m not entirely sure. What would you do?