Dennis Gillings’s net worth over time
Only dates with a published estimate are shown. Nothing is filled in between. Tap or hover a bar to see the source.
See the numbers as a table
| Date | Estimate | Source |
| 2019 | $1.7 billion | Forbes World's Billionaires List 2019 |
| 2020 | $1.4 billion | Forbes World's Billionaires List 2020 |
| 2021 | $2 billion | Forbes World's Billionaires List 2021 |
| 2022 | $2.1 billion | Forbes World's Billionaires List 2022 |
| 2023 | $2.1 billion | Forbes World's Billionaires List 2023 |
| 2024 | $2.4 billion | Forbes World's Billionaires List 2024 |
| 2025 | $2.1 billion | Forbes World's Billionaires List 2025 |
| 2026 | $2.2 billion | Forbes World's Billionaires List 2026 |
| Oct 2026 | $2.4 billion | Forbes Real-Time Billionaires · Forbes real-time estimate |
Where the money comes from
These are the main sources of wealth named in the reporting we cite. No published source breaks the total into exact amounts, so we do not show percentages.
Dennis Gillings’s fortune in real-life terms
Based on the Forbes Real-Time Billionaires estimate above. Median full-time U.S. pay is $65,416 a year ($1,258 a week, BLS, Q2 2026), before taxes. Typical (median) U.S. family net worth is $216,100 (Federal Reserve, 2025 Survey of Consumer Finances).
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Dennis Gillings has an estimated net worth of $2.4 billion, according to Forbes Real-Time Billionaires, Dennis Gillings profile (figures as of October 20, 2026). That is up from $1.7 billion in 2019.
Dennis Gillings is a British statistician and entrepreneur best known for founding Quintiles Transnational, a clinical research company. After teaching mathematics and then biostatistics, he moved from academia into business. In 1982, he launched Quintiles to help make drug clinical trials faster and more efficient. That idea turned into a major healthcare company. He later served as CEO and chairman, and the business became a leading name in clinical research.
His wealth comes from the clinical trials company he built over decades. In 1994, he took Quintiles public through an IPO, giving the company a wider financial base. Before a 2016 merger with IMS Health, Quintiles had reached annual revenue of $5.7 billion. The combined company later used the name IQVIA in 2017. Gillings retired from the board in 2018. Forbes put his net worth at $2.4 billion on its real-time tracker on October 20, 2026.
How Dennis Gillings built his wealth
Gillings made his fortune in healthcare, mainly through the clinical trials business he founded. He started Quintiles in 1982 after working as a biostatistics professor. The company focused on helping drugmakers run studies more quickly and efficiently. That service became valuable as pharmaceutical and biotechnology companies needed large, organized trials. Over time, Quintiles grew into a major contract research organization, and Gillings led it as founder, CEO, and chairman.
A key step came in 1994, when Gillings took Quintiles public through an IPO. That expanded the company's reach and raised its profile in the healthcare industry. By 2016, before merging with IMS Health, Quintiles had annual revenue of $5.7 billion. The business later changed its name to IQVIA in 2017. Gillings stayed involved until retiring from the board in 2018, after building the company into a large global operation.
Forbes net worth timeline
Forbes has tracked Gillings' fortune for years, with estimates moving up and down. It listed him at $1.7 billion in 2019, then $1.4 billion in 2020. The estimate rose to $2 billion in 2021 and $2.1 billion in 2022, staying at $2.1 billion in 2023. Forbes then increased the figure to $2.4 billion in 2024 before placing it at $2.1 billion in 2025 and $2.2 billion in 2026.
The bigger picture is that Gillings' wealth has remained tied to the clinical trials company he created and led. Forbes connects his fortune to that healthcare business, which became IQVIA after the 2016 merger and 2017 name change. On Forbes' real-time billionaires tracker, he was at $2.4 billion in October 2026. That keeps him in the billionaire range built from a business he started himself.
Career and money timeline
- 1971
He accepted a position teaching biostatistics at the University of North Carolina at Chapel Hill.
- 1982
He launched Quintiles to make drug clinical trials faster and more efficient.
- 1994
He took Quintiles public through an IPO.
- 2004
He received a CBE for work in the pharmaceutical industry.
- 2016
Quintiles merged with IMS Health after reaching $5.7 billion in annual revenue.
- 2017
Quintiles changed its name to IQVIA.
- 2018
He retired from the board of IQVIA.
Dennis Gillings net worth FAQ
What is Dennis Gillings's net worth?
Dennis Gillings's net worth is an estimated $2.4 billion, according to Forbes Real-Time Billionaires, Dennis Gillings profile (October 20, 2026). It is an estimate, not an official figure.
How did Dennis Gillings get so rich?
The main sources named in the reporting we cite are: Clinical trials.
Is Dennis Gillings a billionaire?
Yes. Forbes Real-Time Billionaires estimates Dennis Gillings is worth $2.4 billion.
How has Dennis Gillings's net worth changed?
The earliest published estimate we track is $1.7 billion (2019, Forbes World's Billionaires List 2019). The latest is $2.4 billion (October 20, 2026).
What company made Dennis Gillings rich?
His fortune comes from Quintiles, the clinical research company he founded in 1982. The business later became IQVIA after a 2016 merger and a 2017 name change.
Was Dennis Gillings self-made?
Yes. Forbes describes him as self-made, and his wealth is tied to the healthcare company he built.
Sources
- Forbes Real-Time Billionaires, Dennis Gillings profile (October 20, 2026)
- Forbes World's Billionaires List 2019, Dennis Gillings profile (March 5, 2019)
- Forbes World's Billionaires List 2020, Dennis Gillings profile (April 7, 2020)
- Forbes World's Billionaires List 2021, Dennis Gillings profile (April 6, 2021)
- Forbes World's Billionaires List 2022, Dennis Gillings profile (April 5, 2022)
- Forbes World's Billionaires List 2023, Dennis Gillings profile (April 4, 2023)
- Forbes World's Billionaires List 2024, Dennis Gillings profile (April 2, 2024)
- Forbes World's Billionaires List 2025, Dennis Gillings profile (April 2025)
- Forbes World's Billionaires List 2026, Dennis Gillings profile (March 10, 2026)
- U.S. Bureau of Labor Statistics, Usual Weekly Earnings (Q2 2026) (July 2026)
- Federal Reserve, 2025 Survey of Consumer Finances (median family net worth, Table 4) (October 2026)
- Background facts: Wikipedia, Dennis Gillings (accessed October 23, 2026). Used for career facts only, never for figures.
Photo: Richter Frank-Jurgen, CC BY-SA 2.0, via Wikimedia Commons.
Every number on this page is an estimate published by the source named next to it. We never fill in years with our own guesses. How we handle estimates.