Marc Eidlitz & Son started constructing the Federal Reserve Building's structural system after the excavations had finished. The steel framework was in place by the end of 1922, followed by the facade in mid-1923. Some of the 2,600 employees of the New York Fed started occupying their new offices in June 1924. That September, three billion dollars in cash and securities were moved to the vault. The relocation, requiring one hundred round trips, represented the largest ever such movement of money at any one time. Employees had moved into the new structure by the next month. The new building's vault replaced what was formerly eleven separate vaults in five buildings throughout the Financial District. By 1927, ten percent of the official gold reserves worldwide were stored in the vault.