A 92-year-old janitor built an $8 million fortune without anyone knowing. These are the 3 things he did.

Stock markets may experience fluctuations from time to time, but investors who gain enough experience and insights about factors that play a role in determining share prices can become millionaires with the right strategy. That's what worked for Vermont-based janitor and gas station attendant, Ronald Read, who built an $8 million portfolio despite earning a modest salary. But he did it with such subtlety, that even his family was “tremendously surprised” upon learning about his hidden wealth, CNBC reported.

Most people didn't know about Read's hidden fortune until he passed away in 2015, and the estate was revealed. It came as a surprise for the local community as he didn't have the career path that a millionaire would take. Coming from humble beginnings, Read served in North Africa, Italy, and the Pacific theater during World War II, after high school, according to Reuters. He then came home picked up a job at a gas station in JCPenney, and married a woman who had two children. He worked at the facility all his life and never won the lottery or an unexpected fortune.

“He was a hard worker, but I don’t think anybody had an idea that he was a multimillionaire,” his stepson told the local press after his death. His portfolio and strategy were analyzed by experts after his death, and it was found that Read built his fortune by following a few basic steps.

Read had a reputation for being extremely frugal, something that the Oracle of Omaha, Warren Buffett is also known for. According to his friends, Read drove a second-hand car all his life and wore a coat held together by safety pins.  Even in his 90s, he continued to cut firewood for himself to save money.

“I’m sure if he earned $50 in a week, he probably invested $40 of it,”  Read’s friend and neighbor, Mark Richard told CNBC.

When it came to picking stocks, Read was straight-up brilliant. He chose stocks that turned in a profit over a longer time, a strategy that even Buffett recommends. Following his death, the Wall Street Journal analyzed his personal investment portfolio, which included stocks such as Wells Fargo, Procter & Gamble, and Colgate-Palmolive.

Showing Some Resilience

Read lived till the age of 92, which means that he lived longer than an average person while working hard. It was found that he held many of his stocks for decades. Since he prioritized holding long-term positions, the strategy earned him immense returns over time.  With his long-term strategy, the power of compounding also increased his returns.

Apart from the heavyweights, he also picked Pacific Gas & Electric's stocks in 1959 and held onto them till his death. The shares that he bought for $2,380 then, were worth $10,735 by 2015, the publication reported. He even stuck with Lehman Brothers until 2008, when the firm collapsed.

The lifelong resident of Brattleboro, Vermont, left $6 million to his local library and hospital. “It was the talk of the town,” Brooks Memorial Library director Starr LaTronica told CNBC referring to the massive $1.2 million donation.

The remaining $4.8 million went to Brattleboro Memorial Hospital, which Read visited regularly, but just for breakfast. “He always had a cup of coffee and an English muffin with peanut butter,” Read's friend, Ellen Smith, said.