During WW1, War bonds were sold, These bonds were called Liberty bonds. These bonds were to help finance the war.
The first issue of these bonds was not all sold, which did not make Treasury Department look very good. This eventually involved a launched of a massive campaigns using posters, and movie stars to make it popular . This was a major movement in American history during world war one, that helped make investment public. It was an important way to raise funding for the war.