After fiddling around with the stock market and the parameters by which the shares gain/lose value, I have come across something interesting:
(Only character I'm using for this is Michael, since I have completed most of the missions for him, and completed the game already, I let the other two handle their side missions while using Michael as the main money maker, also for demonstration purposes you should take a look at
this).
Using Michael makes me use the LCN exchange for all transaction purposes, after following several investments I have found that the most variation of a stock value is the "AUG"(AuguryInsurance, which prices vary from 237 in a low to a 491 in a high, which would be 254 range of change), therefore to invest on this stock you have to wait until the price has fallen into 230-240 value to invest on it, in this case investing:
Initial investment: 10 million/Friday 21:00 hrs(aprox) -> Stock value=240 ->41665 stocks(aprox)
Final revenue in a high: Stock value=480/Tuesday 00:00 -> 41665x480=19'999200 in AUG stocks sold.
So, from an initial investment of 10 million, I ended up earning almost twice as the investment. Now the trick is to set threshold to when the stock is at it's minimum(and therefore viable), this threshold for AUG would be between 240 to 270, and wait for it to climb(you have to be patient for this) so the stock goes over the 410 threshold(which is my set for higher revenue as it seems randomized, I haven't had enough time to actually know if it cycles or not).
Thus far I have owned the one of the cinemas and I have purchased all the other available proprieties except for a remaining cinema, and the golf club.
I would like to know if the AUG stock works in the same way for anybody else.