(MONEY Magazine) – For Natesan Murthy, 65, selling shares of a beloved stock can be painful. "When you manage your own money, there is a tendency to become emotionally attached to holdings," he says. "It's one of the greatest challenges you face as an investor." After a decade of average annual returns of 20%, his portfolio dropped by a third in the recent bear market. Murthy, who emigrated from Calcutta in 1967 with his wife Leela, now 63, and $7.50 in his pocket, retired five years ago from his job with a large oil company. The bulk of his savings (well over a million dollars) comes from gains on his stock and fund holdings. Now that he's recouped much of his losses, he uses stop orders to force himself to sell if a stock falls 15% to 20%. "I'm more self-disciplined as I get more mature." --C.W.