Samsung Electronics reported on Thursday a 55% drop in second-quarter operating profit as delays in high-bandwidth memory chip shipments and U.S. export curbs on advanced chip sales to China continued to drag on its key semiconductor division. The world’s largest memory chip maker posted 4.7 trillion won ($3.37 billion) in operating profit for the April-June period. The result was in line with its earlier estimate of 4.6 trillion won, which had disappointed investors.