The Oracle logo is shown on an office building in Irvine, California, U.S. June 28, 2018. REUTERS/Mike Blake

LONDON, Dec 11 (Reuters) - The cost of insuring Oracle debt against default surged on Thursday to its highest in at least five years, after the company's results missed forecasts, reigniting investor concern about its massive borrowing to fund its push into AI.

The company's five-year credit default swaps, a derivative that pays bondholders in the event an issuer defaults, rose by nearly 12 basis points on the day to 139 bps, according to S&P Global Market Intelligence.

This was the highest since at least September 2020, according to LSEG data.

Oracle shares were down 13% in pre-market trading, suggesting a slide at the opening bell later.

(Reporting by Amanda Cooper; Editing by Dhara Ranasinghe)