Green followed a contrarian investing strategy, in her words, "I buy when things are low and nobody wants them. I keep them until they go up and people are crazy to get them. That is, I believe, the secret of all successful business." Green invested the interest from her father's trust fund, once again investing as her father had done, in Civil War bonds, which paid a high yield in gold, augmented by railroad stocks. Her annual profits during her first year in London, amounted to $1.25 million, while the most she ever earned in a day was $200,000. Green went on to say, "I believe in getting in at the bottom and out on top. I like to buy railroad stocks or mortgage bonds. When I see a good thing going cheap because nobody wants it, I buy a lot of it and tuck it away." Hetty's discounted greenbacks, bought during the Civil War, were increased in value when Congress passed legislation in 1875 backing them with gold. As Hetty said of her investing philosophy, "Before deciding on an investment, I seek out every kind of information about it."