text: how do i find out if i own stock in a koch oil? my granfather and father died with in a short time of each other and my grandpa owned stock in koch oil.my mother remembered hearing about the stock when handling their estate but assumed that the companies didn't exist anymore.so i need to know how to find out what happened to the stock. any suggestions on how i go about doing that? you should check your grandfather's will, and try to get in contact with any lawyers or accountants/financial advisors that may have worked with your grandfather (especially anyone who helped him with his will, if he had one). also, it might be wise to look for old tax returns.