Cathay Pacific Airways Ltd. is winning back stock investors as the carrier seeks to slash costs after its worst loss in more than 20 years. Having a friend in Goldman Sachs Group Inc. doesn’t hurt, either. The shares have jumped 6.2 percent this week, the best performance on Hong Kong’s Hang Seng Index, which is little changed. The stock rallied after Goldman Sachs put Cathay Pacific on its conviction list, calling the company unloved and misunderstood. Investors are underestimating the airline’s potential to boost earnings, Goldman analysts led by Ben Hartwright wrote in a note, citing improving demand and supply. Betting against the company was a good idea the past two years, when the stock plunged 40 percent in one of the worst performances among global airlines. Yet the shares have staged a steady recovery this year as the Hong Kong-based carrier looks at ways to cut costs, including pilot compensation, after ill-judged fuel hedges and rising competition saw it suffer losses. The company still has some way to go to convince everyone: its shares are the lowest rated by analysts among members of the Bloomberg World Airlines Index. But at least three brokerages have upgraded Cathay Pacific in the past two months, and Goldman, the most bullish of the lot, sees the shares rising a further 15 percent over the next year.