Janus Henderson is forging a wide-ranging partnership with Guardian Life, the latest investment firm to carve a larger role managing insurance money.

The agreement includes a mandate to manage $45 billion of the insurer’s bond portfolio, executives at the two companies said. Guardian Life also agreed to invest as much as $400 million to seed new initiatives at Janus Henderson, including credit products, and receive warrants that grant it the right to buy stock in the investment manager at a predetermined price.