Swiss Re had been entertaining the deal involving SoftBank amid industry-wide pressure in recent years from falling prices and intense competition, hoping a new partner might open new streams of revenue from the fast-growing and unsaturated insurance market of Asia.

Initial reports this year that SoftBank wanted as much as a quarter of the Swiss company were winnowed in April to not more than 10 percent. Swiss Re, which did not give a reason the potential deal failed, had ruled out a capital increase to aid SoftBank's entry, meaning the Japanese investor likely would have had to buy shares on the open market.

"Swiss Re will continue to implement its technology strategy with a combination of in-house developments and third-party collaborations," Swiss Re said in a statement.

"In this context, the company will also further explore business ideas between Swiss Re's operative entities and the portfolio companies of SoftBank."

Analysts had said SoftBank was attracted to Swiss Re's research capabilities, undervalued stock and cash generation.

(Reporting by John Miller; Editing by Clarence Fernandez)