My mistake selling CBG

I sold about 60% of my remaining position in CB Richard Ellis yesterday. I had already sold half my shares after the stock doubled from my purchase price. The stock was up 200% from my purchase price yesterday, so I decided to sell some shares.

The question I wrestled with yesterday was whether to sell the whole thing. My investment thesis on CBG was that it was dramatically oversold (as were a lot of stocks). This was a stock I knew pretty well having covered it at my last job. The point is that I didn't buy the stock because I thought the fundamentals of the commercial real estate market were about to get a lot better. Ultimately, this thesis was based on an improvement in sentiment, not intrinsic value. I think sentiment has largely normalized now so that trade is over. For the stock to rise dramatically from here, either sentiment needs to swing to the exuberant side of the spectrum (very unlikely in my opinion) or the fundamentals need to improve enough to raise Intrinsic Value. I have been reading about some renewed interest in commercial real estate from foreign investors, but ultimately, I think fundamentals will come back slowly.

So why didn't I sell the whole position. I think I fell victim to some classic thinking traps. CBG has been my best performing stock and I like owning it as a result. Keeping a small position serves as a trophy of sorts. Second, it is simply hard to sell a stock when it is going up. The fear of missing future gains is powerful and I think I was lured in.

Just wanted to share some of what I'm learning.