The biggest insight Milken was that you could create junk bonds. Lookign back this seems trivial, but no one else had thought of doing this. Junk bonds

The biggest insight Milken was that you could create junk bonds. Lookign back this seems trivial, but no one else had thought of doing this. Junk bonds used to be the so called "fallen angel", bonds issued by highly rated credit companie sthat later were downgraded. All of the bonds trading in the market were bonds that lost their rating. The big idea was that companies with poor credit could issue bonds, which no one had realized yet. This opened up a lot of capital to firm, some of which were startup in nature, that previously couldn't get capital. This drove real economic growth that built real things.