I am 99 percent sure it is about volume sold/purchased. A theory used to be $10G traded but that has been rejected.
It could be value sold/bought but only to system or only to other players. It could be sales only or purchases only. It could be amount instead of value.
There is only one thing to do - keep buying and selling. If you are good at it there is a profit to be made in the process.
Another possibility could be value or amount of stocks held. I think that is wrong since I once transferred all my stocks to a friend to get the 100 benefits merit and he did not get the analyst award (;I have it myself);
I haven't got any particular tips, but I can tell you what I was doing at the time I got mine.
I was saving up for a tcb benefit, every 1-2 weeks I would buy about 10million worth of shares. I did this for quite a while and then I got the honor.
I think I may have also bought a couple of benefits a week or so before I started saving for it.
By Penicillin 
So, I got the stock analyst award last night. As this has been discussed in several threads and nobody knows what triggers it I took special note of the conditions.
1. I bought a benefit block of IOU
2. The forecast was poor and it remained poor after additional price updates so I don';t think the forecast had anything to do with it.
3. The stock continued to trade down after I bought it so I do not think it is a matter of picking an exact bottom or top.
4. I told a friend about it and she did the exact same thing as I did before the price changed and she did not get the honor.
5. There was plenty of stock offered before and after I bought it but theoretically I could have bought the last of the player offered stock vs NPC offered.
6. I do not know if the demand was different before and after I bought it. It said "average".
7. I buy and sell stocks a lot. I am sure I would have crossed over any total volume trigger a long time ago.
i have that honour too..as stated above no one can confirm what triggers it
but i remember correctly how i got it
i was continuously buying shares of fhc for few hours as the prices were lowest of all times...i hadn't sold any shares during those times..so i think you need to actively buy or sell shares to get that honour..it doesn't matter whether u buy 100's or millions of shares..u just need to actively buy shares