Bolt, Beranek & Newman Inc, Cambridge, Massachusetts, is stuck with its tenuous triple-C-plus credit rating at Standard & Poor’s Corp on its $74m 6% convertible subordinated debentures due 2012, but the outlook is positive and the implied senior debt rating is Single-B. The rating reflects the challenges of building its Internet business and the pressures facing its other operations, somewhat offset by its success in designing and managing communications networks, the agency said. Good growth is possible as it acquires or develops similar Internet access operations in additional areas but the company faces significantly stronger competition for profitable value-added services, while its ability to meet the demands of the rapidly evolving commercial marketplace is uncertain, Standard & Poor’s says, adding that it believes Bolt’s return to profitability, previously expected within the next few quarters, could be delayed by further software and marketing investments and the costs of expanding the embryonic Internet access business.