The phrase "amassed a small fortune" is correct and usable in written English.
You can use it when referring to someone who has accumulated a significant amount of wealth, often over time.
Example: "After years of hard work and smart investments, she has amassed a small fortune."
Alternatives: "accumulated a modest wealth" or "gathered a considerable sum."
Her father, a chemist, teacher, and entrepreneur, had amassed a small fortune manufacturing baby food.
Fernández knew that Felipe Capitaine had amassed a small fortune and that he was very well-connected politically.
And he has amassed a small fortune - earning 55 million dollars (over £36 million) in just one year between May 2011 and May 2012, according to Forbes magazine.
A former mechanical engineer at General Electric, he amassed a small fortune from Finagle a Bagel, a chain of bagel shops he built in the Boston area.
One of the Southwest's most enterprising businessmen in the pre- and post-Civil War era, he had amassed a small fortune from his shipping business and pioneering ventures in cotton, livestock and mining.
By the time he was thirty-five, hadhamassedsed a small fortune, but he never considered marriage and had no real friends, though he had perfectly normal relationships with people he saw on a daily basis.
He moved to New York, "with the intention of following in the footsteps of Bill Cosby and Richard Pryor, hopefully amass a small fortune, get a great apartment, buy a grand piano, plonk myself down and write all the beautiful music in the world".
After inheriting money in his twenties, Douglas managed to amass a small fortune in "the questioned documents business," something to do with exposing forged Kundera diaries and papers from the Dreyfus Affair.
Jon Kest, the executive director of New York Communities for Change, who is one of the prime organizers of the new coalition, said on Thursday that his opponents had been "amassing a small fortune to try and buy the support of mayoral candidates with a massive advertising campaign".
Right now the Sperlings could use a dose of both smarts and luck, if only to disprove that old saw that the fastest way to amass a small fortune is to first have a large one.
Meanwhile, he amassed a modest fortune through investments in banking, electricity, gas, rubber, and sugar.
