Any western company that persuades a foreign bidder to part with $1.75bn (£928m) in return for a chronically unprofitable business would normally earn kudos for clinching a smart deal. But not, it seems, in Washington, where political resistance to IBM's proposed sale of its personal computer division to China's Lenovo is growing.

Three Republican chairmen of congressional committees are urging a full investigation of the deal on national security grounds. It is reported also to have aroused concern among members of the committee on foreign investment in the US (Cfius), the shadowy inter-agency body that vets foreign takeovers of US companies.