One of the most difficult aspects of investing is sticking to a disciplined strategy and avoiding the pressure to sell when your positions are down. In general, I am a proponent of the "never sell" ideology as it eliminates this pressure and allows you to focus on the long-term. However, today I sold $MTTR at a substantial loss (~60% from initial cost basis). Luckily, the position was a relatively small size and only impacted my overall portfolio by ~2% (which arguably is much higher than it should have been given the speculative nature of the investment).

I didn't sell because I lost confidence in the long-term prospects of the business. I sold because I believed there were better places to park money given the crazy valuation at which I bought in to the company (~20x sales). The market drawdown has presented what I view to be some great opportunities to park long-term capital, and I preferred to orient my portfolio towards these more stable names ($GOOGL for one) rather than a more speculative investment such as Matterport.

Another important reason I sold is because of the mental drag I experienced owning the company. I believe in the technology, but I am far from an expert in the area. I found myself frequently fretting over the possibility of another company developing a better technology given the large market opportunity, early stages of penetration, and what I considered a lack of a deep moat. Selling, though painful, has removed these emotional stresses from my investing activity and allowed me to double my focus on finding great businesses to hold for the long term.

It's painful to sell a stock you planned to hold for a much longer period. However, I believe it's important to learn from your experiences and understand your emotional makeup in the context of your goals. My goal is to compound wealth over the long-term, and I felt I could accomplish this better by putting my money into more proven, established businesses.