My portfolio is being battered at present, so I'll try to cheer myself up by recalling happier times!
I've made some investment decisions that worked out well - as well as some that had terrible outcomes! - but most good and bad outcomes were pure luck. For the purposes of this question, I decided that lucky wins don't count, that I had to know in advance that the investment was going to deliver a brilliant outcome.
But how can you know that an investment is a certain winner without breaking the law by insider trading?
I can recall only one investment in my entire life that meets that criterion. Surprisingly for those who know my antipathy to bonds, it was a bond!
In 2011, when the Irish economy was on the floor, I noticed that the Irish Life 5.5% Subordinated Bond 2049 was trading at €63 per €100 of nominal stock. That's a running yield of 5.5%/.63 = 8.73%, with the prospect of a bonus of €37 for every €63 invested, or over 50%, at maturity.
Why was the bond available at a bargain basement price? Because the market confused Irish Life Assurance with Irish Life & Permanent, which was a basket case at the time. Irish Life Assurance was a completely separate legal entity, but the market didn't know that. I gather that only I and an American hedge fund realised that the market had it all wrong.
I bought lots of the bond for my ARF at 63. The price was down to 55 at 31 December 2011, so my investment was standing at a considerable loss, but I wasn't worried. I knew it had to come right at some stage.
In January 2013, I bought more at 75 and more again at 83.
Then, in July 2013, everything changed when Irish Life was acquired by Canada Life. The price of the bond jumped.
I sold my entire holding gradually between 2014 and 2016 at prices ranging from 99 to 103.26.
Thus ended my most successful - actually, my only - investment coup, ever.