Hetty Green seems to have been given a rather frightful sobriquet for a woman who came from a Quaker family and was by several accounts quite religious. Her reputation may have been the result of being a successful businesswoman in an age of businessmen or it may have been a result of being a little ruthless in her success. Whatever the reason, Hetty Green was a rather formidable woman. How else would she have been able to amass so much money and be considered the richest woman and one of the richest people in America?
Harriet Robinson was born in New Bedford, Massachusetts in November 1834. Her family had made millions with their whaling fleet and shipping interests. Hetty seems to have developed her financial skills at a very early age after spending considerable time with her grandfather Gideon Howland who would talk to her about financial matters and encourage her to read financial papers. Hetty married a wealthy Vermont man, Edward Henry Green, and did something unusual for the day – she asked the prospective husband to renounce all rights to her money.
Although formidable, she was also quite talented and very successful. Through her own efforts, she parlayed the money her father left her (varying accounts put at about $5 – $7 million dollars), as well as money left to her by her spinster aunt, Sylvia Ann Howland, into an even bigger fortune by investing in real estate and railroads. In 1899 an article in the San Francisco Call estimated her worth at about $60,000,000 while an article titled “The World’s Richest Two Dozen” in the June 2,1905 Seattle Republican estimated her worth at $100,000,000. When confronted with the question in 1905, she is quoted in an article in the National Magazine, as saying she was worth less than everyone thought because “rich people are always worth less than report has it.”  Due to her wealth and interests, her name was linked with the likes of Russell Sage, JP Morgan, John D. Rockefeller, and other financiers and tycoons of the day.
Like many successful people, she was often asked for financial advice. On being asked what a woman with a few hundred dollars should do with that money, she said real estate was the best investment – especially if bought at auction when the prices were lower.
“I regard real estate investments as the safest means of using idle money… Let a woman watch and see in which direction a city is going to develop and buy there.” 
Hetty felt that for women “safe and low was better than risky and high.” For her:
“There was no great secret in fortune making. All you have to do is buy cheap and sell dear, act with thrift and shrewdness and then be persistent.” 
Her advice to others followed her own practices – her real estate investment strategy was to buy property cheap when nobody wanted it, hold onto it until there was interest, and then sell high. She was less active in stocks, especially industrials, because she felt Wall Street was “no place for a woman,” but did have a fondness for government bonds, despite the fact they didn’t pay a high rate of interest.  However, when she did buy stocks she preferred buying them for investment and not for speculation and would “never buy on a margin.” She was definitely one to pay attention and seize any opportunities that arose. In the book The Witch of Wall Street (1936), there is a chapter on the Panic of 1907 where Hetty assessed the events of the year. She indicated that she knew the panic was coming and goes on to say that she made every effort to have cash on hand in order to lend to those that came to her – including the city of New York, to whom she lent over a million dollars in return for short-term revenue bonds.
Many of the stories written about her were rather sensational. A San Francisco Call article from March 26, 1899 indicated that she never paid taxes, lived in cheap lodgings, and believed so strongly that there was a conspiracy of lawyers who were out to get her, that she hired a bodyguard and began carrying a pistol. The article went on to say that she and her husband had stopped living together because she didn’t respect him after he lost all of his money and hinted that her son lost his leg because she wouldn’t pay the money to fix it properly. 
Most articles written about Mrs. Hetty Green mention the numerous lawsuits over family wills and other issues in which she was embroiled for most of her life. A 1910 article in the Salt Lake Herald Republican detailed how Hetty supposedly tried to break her aunt’s will with a forged one because she wanted all of her aunt’s estate (she lost the case). Another article titled “Mister Hetty Green” said her husband was on an allowance.
Hetty died in July 1916 in New York City. According to her obituary in the New York Times on July 4th, her estate was estimated to be about $100,000,000. When the text of her will was printed in the July 23, 1916 New York Times, the mystery of how much she was worth continued - her will did not stipulate an inventory of the estate which would have determined the exact amount of her final estate. 
As to the origin of the Witch of Wall Street nickname, in the Witch of Wall Street by Boyden Sparkes and Samuel Taylor Moore, the authors had this to say:
“When, however, Mrs. Green next appeared in New York she was wearing her mourning and for years thereafter she was never seen on the street except with a heavy swathing of black veil. It was this garment, perhaps, as much as anything that caused her to be spoken of as the Witch of Wall Street.” 
If you want to read more on this interesting woman, there are several books that may be of interest:
- Hetty : The Genius and Madness of America’s First Female Tycoon
- Hetty Green, A Woman Who Loved Money
- Witch of Wall Street
- The Richest Woman in America : The Life and Times of Hetty Green
- The Day They Shook the Plum Tree
1. Ford, Carol. “Hetty Green, A Character Study”, National Magazine, September, 1905. p. 633.
2. Ford, p. 632.
3. Ford, p. 633.
4. Ford, p. 633.
5. “Hetty Green the Richest Woman in America.” San Francisco Call, March 26, 1899, p. 18.
6. “Hetty Green’s Will is Read in Court.” New York Times, July 23, 1916, p 1.
7. Sparkes, Boyden. The Witch of Wall Street, Hetty Green. (Garden City: Garden City Publishing, 1936) p. 265