Monaco is a tiny nation of fewer than 40,000 residents. Although this technically makes it a city-state, the country's small population might be better off than any other in the world. In 2018, Forbes reported that almost one-third of the country's population, or 32.1%, had assets over $1 million – not including the value of their homes. According to the report, Monaco had the world's largest density of people whose net worths qualified them as millionaires. Additionally, there are more billionaires in Monaco per capita than anywhere else in the world.

Monaco is an attractive destination for the world's elite. There is no income tax in Monaco, and corporate taxes remain very low by world standards. The low crime rates and Mediterranean waterfront do not hurt either. Here are the country's top billionaires by net worth, according to Forbes. 

Tatiana Casiraghi

Monaco is one of the few places on Earth where the wealthiest resident is a woman. Tatiana Casiraghi, better known as Tatiana Santo Domingo, is heiress to a beer empire and the wife of Prince Andrea Casiraghi of Hanover, who also happens to be fourth in the line to the Monégasque throne. She ranked at 1,103rd-place on Forbes' billionaires list. Her net worth was listed as being $2.2 billion. 

Casiraghi inherited much of her wealth from her grandfather Julio Mario Santo Domingo, whose Colombian brewery, Bavaria, was sold to SABMiller plc for billions in 2005. Tatiana received one-sixth of Julio Margo's fortune following his death in 2011.

Born in New York and raised in Switzerland by Colombian and Brazilian parents, Tatiana was studying in a boarding school just outside of Paris when she met Andrea Casiraghi. She is an active socialite and philanthropist, even launching the Muzungu Sisters business with Dana Alikhani in 2011. The company buys handmade garments from local artisans and resells them. She lives in Monaco with her son, Alexandre Andrea Stefano Casiraghi.

David Nahmad and Ezra Nahmad

Brothers David and Ezra Nahmad are two of the most successful art dealers in the world. They are self-made experts and enthusiasts, and they have always held their assets jointly. David's net worth was estimated by Forbes at $1.9 billion, while Ezra's was at $1.5 billion. The only substantive difference between their respective fortunes comes from David's investment portfolio, which he actively manages and is valued at around $350 million as of 2018. David was ranked by Forbes as the world's 1,284th-richest person, while Ezra placed at number 1,561. 

The Nahmad brothers claim an impressive art inventory full of blue-chip pieces from Monet, Rothko, and Matisse, as well as more than 300 genuine Picassos. Their collection has been described as jointly modern and Impressionist. The brothers were born in Beirut, Lebanon, after their family moved away from Syria following a wave of anti-Semitic violence. The two fled to Monaco and New York after danger reached Lebanon.

David and Ezra were always enterprising, even at a young age. For example, the two regularly skipped high school classes to trade on the Milan Stock Exchange. They found their love of art at a Juan Gris exhibit in Rome, where they decided their appreciation of trade and art could be balanced through art dealings. As the director of the Museum of Contemporary Art in Los Angeles once noted, the Nahmads were like "a major brokerage firm in the stock market," except in art.

Lily Safra 

As a legendary, and perhaps infamous, socialite, Lily Safra, whose net worth was reportedly $1.3 billion, is a Brazilian philanthropist who moved to Monaco part-time in the 1970s after marrying banking mogul Edmond Safra. Edmond, who was her fourth husband, passed away in 1999 during a highly publicized arson fire at the couple's Monaco penthouse. The Safras had homes in Monaco, New York, Geneva, and the French Riviera. Edmond left part of his vast fortune to Lily, while the majority was passed on to the Edmond J. Safra Philanthropic Foundation. 

Safra is highly celebrated for her devotion to charity, particularly through the foundation. She supports education, medicine, scientific research and humanitarian relief in more than three dozen countries. Safra has also had four high-profile marriages, all to wealthy businessmen, which ended in two divorces, one suicide, and one death by fire.