You have the following columns. stock price, stock value, safe, cash, shares(bot, sold), shares owned, portfolio control, buy(sell) advise, market order, interest, portfolio value.

Now the formulas.

Stock value = current price * number of shares from line above
Safe = .1 * stock value
Cash = last rows cash ' last rows market order + last rows interest
Buy/sell advise = last months portfolio control ' this month stock value
Market order = buy sell advise - safe value
Interest is given
Portfolio control = last months portfolio control + round(.5 * this months market order,0)
Shares bought or sold = round(market order/stock price, 0)
Shares owned = last month shares owned + shares bought or sold
Portfolio value = cash + stock value

Now an example.

Assume this month the stock price is 10,the stock value = 5,000, cash = 5,000, shares bought = 5,000, portfolio value = 10,000, and the interest is 22.00
Next month the stock is 8.
Stock value = 4,000 = stock price * number of shares
Safe = 400, = .1 * Stock value
Cash = 5,022. Cash + interest
Buy sell advise = 1,000 last month portfolio control ' this months stock value
Market order = 600. Buy sell advise ' safe value
Shares bought or sold = 75. Market order divided by price
Portfolio control = 5,300 = last month portfolio control + .5* this month market order
Interest = 19 ' given
Portfolio value = cash + stock value = 9,022.

Is there a place where I can upload a spreadsheet. I had to play with this a while before it became familiar to me. Cathy, can you fix anything I did wrong?