Whether it comes down to valuation concerns, risk exposure, changes in strategy, or any other reason, it’s inevitable that there will be times when investors ought to consider selling all or part of their holding in stock. What it does: AB Dynamics designs, manufactures and supplies advanced testing, simulation, and measurement products to the global transport market. By Paul Summers. Having had my finger over the ‘sell’ button for several months, I’ve now disposed of my position in vehicle testing firm AB Dynamics (LSE: ABDP). To be clear, this isn’t because I think the company is doing anything wrong. Indeed, it’s been a profitable business for many years and continues to boast a robust balance sheet. Conceivably, AB could also do very well as autonomous driving becomes a reality. No, the reason I’ve sold is purely down to the valuation. Despite only growing revenue by 5% in the first half of FY24, the stock still trades at an eye-watering 31 times earnings at the time of writing. In the absence of a near-term catalyst for trading to improve, I can’t see the share price moving significantly higher for a while. Whether I come to regret my decision remains to be seen. As things stand,...