My oldest investment is my Intel stock options which I exercised in 1987 at price $.625/share considering that they pay $.90 a year a dividend it is been a very good investment even if this century has been pretty bad.
My mom has shares of AT&T, which she inherited from my dad, who turn inherited them from his aunt. I about 15 years ago I spent a entire weekend trying to establish the cost basis for these share before giving up, my mom is going to die with those shares. As far I can tell the original purchase was 60 share of the original A&T company in the early 1950 and a DRIP plan for roughly 25 years. Since that time through an amazing number of stock splits, spin offs, and mergers its has turned in 1094 share of AT&T worth 40K and $8K worth of Comcast shares, and few hundred dollars worth of stocks.