A crucial system for making payments to insurers from the federal Obamacare marketplace, HealthCare.gov, has yet to be built, a senior government IT official admitted Tuesday. The official, Henry Chao, visibly stunned Rep. Cory Gardner (R-Colo.) when he said under questioning that a significant fraction of that online insurance marketplace has yet to be constructed. (Read more: Low-bamacare enrollment) Getty Images Henry Chao, deputy CIO and deputy director of the Centers for Medicare and Medicaid Services' Office of Information Services, testifies during a hearing before the Oversight and Investigations Subcommittee of the House Energy and Commerce Committee. "We still need...