Complex Formula Help Needed

Hi

I'm new here and am actually pretty chuffed to find a forum specifically for Excel. I've used excel a lot for work but beyond basic functions I've not done much.

I have a problem that needs a bit of explaining. I am trying to design a formula that, depending on market conditions, alters the position of a financial portfolio. There is a set of conditions that needs to be followed. Below is the detail:

Suppose you have a portfolio ("Portfolio" or "PV") of $100. Of this $100, $75 is placed in the stock market (called "risky assets", or "RA"). $20 is kept as cash ("Cash" or "CA"), and 5% is collected as fees ("fees"). So:

PV = RA + CA + Fees
100 = 75 + 20 + 5

The fee is removed from the equation, leaving:

PV = RA + CA
95 = 75 + 20

The conditions are thus:
1. If the PV rises above 110, then $5 is taken from CA and placed in RA. Since the portfolio can only rise through an appreciation of RA (cash is constant and the fees are removed from the equation), when RA hits 90, 5 is taken from CA and added to RA:

PV = RA + CA
110 = 95 + 15

2. The same process is repeated if PV rises above 120, $5 more is taken from cash and placed in RA. (i.e. if RA hits 105)

PV = RA + CA
120= 110 + 10

3. The same process is repeated if PV rises above 130, $5 more is taken from cash and placed in RA. (i.e. if RA hits 120)

PV = RA + CA
130= 125 + 5

3. The same process is repeated if PV rises above 140, $5 more is taken from cash and placed in RA. (i.e. if RA hits 135)

PV = RA + CA
140= 140 + 0

Beyond this there are no more rebalances, as CA is 0.

However, the opposite occurs when the value of the portfolio falls. If at any point PV falls below 135, 5 is removed from RA and placed in CA. If PV falls below 125, 5 more is removed from RA and placed in CA. If PV falls below 115, 5 more is removed from RA and placed in CA. and if PV falls below 105, 5 more is removed from RA and placed in CA. Once CA hits 20, there are no more rebalances.

I have tried this using IF formulas, but I cannot get it to work. I wonder if using more advanced programming is needed. I have enjoyed the process so far and made some progress, but I feel I am stuck. and my boss is starting to breathe down my neck.

I would appreciate any help that could be provided to me for this challenge!

Thanks