Is there a way to check for unknown investments that may be under my SSN?

I have a bit of a rough situation. When I was a baby, my grandfather obtained my SSN from my parents because he stated that he wanted to purchase some investments to help fund my college education. He is listed as custodian on the investments and I am listed as the UGMA (recipient of the Uniform Gift to Minors Act). Many people have advised me to have the investments transfered to my name as I am now over 18 years of age. This would have many unfavorable outcomes with my grandfather. He has all W-9s mailed to him and even though I am listed on the account, I am unable to have a copy of a W-9 mailed to me for investments. Does anyone know if there is a way for me to find out if there are any other investments that he may be holding under my SSN without my knowledge? My grandfather won't talk about any of this, so I don't even know if he is paying the taxes. I have a right to know what is listed under my SSN! Any advice would be greatly appreciated!

Sorry...I had stated in my post above that the forms were W-9s. There is a correction. The Form I am referring to is the 1099.

Request free credit reports from all three credit agencies. Those reports should list all banking and investment accounts associated with your name. Then contact all the companies on the credit reports with accounts in your name. You can also contact the various investment companies in your phone book to find out if there are accounts in your name.

I would go to the SSN office and see if they can help they can bring up any thing that has been done with your SSN.

If the investment pays a dividend you should receive an annual 1099-MISC from the government, and would be able to request these from the government.