There are grounds for both optimism and concern on the Y2K readiness of large U.S. industrial companies, indicates a new survey by the National Assn. of Manufacturers (NAM) and Edward Yardeni, chief economist at the New York investment firm of Deutsche Morgan Grenfell, an arm of Deutsche Bank AG. More than 80% of the respondents to the poll reported that their firms' Y2K projects are more than 75% complete. All the firms reported their preparations will be finished by yearend, although 22% said they won't conclude the task until the fourth quarter. Thirteen percent indicated that they are fully ready now. Despite these favorable results, business leaders should not rest easy, warned Yardeni, who was one of the first economists to call attention to the Y2K peril. "The biggest companies, while most prepared, also are the most vulnerable to the weaker links in the global supply chain," he says. Added NAM President Jerry Jasinowski: Significantly, the economies of the developing world are far behind the U.S. economy. Given the connectedness of the global marketplace, these are serious concerns." The anonymous poll, conducted via the Internet among large manufacturers by Yardeni, drew 96 responses. About 75% of the firms said they operate on a global basis, which makes them vulnerable.