Final answer:
During the 1907 panic in the U.S., known as the 'Bankers' Panic,' C. J.P. Morgan served as a de facto lender of last resort by providing loans to faltering banks and restoring financial confidence.
Step-by-step explanation:
During the financial crisis in 1907, known as the “Bankers' Panic,” private banking tycoon J.P. Morgan acted as a de facto lender of last resort. Banks had ceased lending due to fears of insolvency, which put the U.S. economy at risk. However, J.P. Morgan stepped forward and provided loans to banks that were teetering on the brink of failure. This move helped to restore confidence in the financial system. Therefore, the individual who served as a de facto lender of last resort during the 1907 panic was C. J. P. Morgan.