15: Chayaphon Moonsri — 54 wins (18 knockouts), unbeaten.
Weight class: Minimumweight.
Nationality: Thai.
Why he's ranked: It says a lot that Moonsri, also known as Wanheng Menayothin, surpassed Floyd Mayweather's individual 50-0 boxing record with little more than a whisper in the mainstream sporting press.
Mayweather, the most technically-brilliant pugilist of the last 25 years at least, had the benefit of a powerful Las Vegas-based promoter, the gift of the gab, and then major broadcasters around the world to trumpet his achievements.
Moonsri, in contrast, competes exclusively in Thailand, his fights are rarely seen outside of Asia, and he fights in a weight class very few care about; minimumweight, where athletes weigh no more than 105 pounds (48 kg).
This does not detract from one significant thing — he has been winning since 2007 and has been a champion since 2014. An all-Thai fight against Thammanoon Niyomtrong, the WBA champion, could elevate Moonsri's ranking, as could a title in the weight class above, at light flyweight.
Championships won: WBC minimumweight title (2014 to present).
14: Gervonta Davis — 22 wins (21 knockouts), unbeaten.
Weight class: Lightweight.
Nationality: American.
Why he's ranked: Want to annoy a lot of boxing fans? Whack Davis in your pound-for-pound lists because, boy, does this dude have his haters.
Davis is promoted by Mayweather Promotions CEO Leonard Ellerbe, who is building interest in the lightweight in the fighter's home city Baltimore, in "black Hollywood" Atlanta, and, eventually, the fight capital of the world, Las Vegas.
Business Insider met Davis when he was in London in 2017 ahead of his knockout victory over Liam Walsh, where he was flanked by a big entourage, Mayweather, and Ellerbe.
As an athlete who finished his amateur career with a 206-15 record, Davis has extraordinary finishing ability to complement his technical base — something he has shown for years.
He is next in action on Saturday, December 28 where he fights for a world title in a second weight class against Yuriorkis Gamboa, a fighter he is expected to destroy before those influential figures who surround him attempt to elevate him in pound-for-pound lists around the world by booking him into bigger and better fights.
Championships won: World titles at super featherweight (2017 to present).
13: Jermall Charlo — 30 wins (22 knockouts), unbeaten.
Weight class: Middleweight.
Nationality: American.
Why he's ranked: Jermall Charlo is becoming increasingly known around the world as he is doing one critical thing — winning.
After beating super welterweight opponents like Cornelius Bundrage, Austin Trout, and Julian Williams in championship fights, Charlo moved up to middleweight and told Business Insider recently that the division, which has seen Mexican and European fighters vie for supremacy, is now an American weight class again, and it's all because of him.
As a 29-year-old, Charlo has entered his prime as an athlete and a fighter. He applies pressure, has respectable punching power, and has aspirations to take out the division's big names. If he does, he'll find himself replacing them in lists like these.
Championships won: WBC middleweight title (2019 to present) and the IBF super welterweight title (2015 to 2016).
=T 12: Tyson Fury — 29 wins (20 knockouts) against one draw.
Weight class: Heavyweight.
Nationality: English, with Irish traveller heritage.
Why he's ranked: A clip of Fury uppercutting himself in the face during a 2009 win over the journeyman fighter Lee Swaby haunted the heavyweight for years.
Detractors would use footage as part of their criticisms that Fury would amount to little, but his victory over Wladimir Klitschko changed everything. Fury out-thought, out-boxed, and out-pointed Klitschko, a long-reigning champion at the time, in a 2015 bamboozling for the ages.
He did not fight for three years, suffering depression and saying he wanted to crash his Ferrari at 190mph so he could crush it like a Coke can. Still, he returned to the ring on form, winning twice, before being one of only two athletes to take Deontay Wilder the 12-round distance in 2018.
That Wilder draw is the only minor blemish on Fury's record, a blemish his promoter Frank Warren told Business Insider was unjust as Fury had done enough to win.
The rematch, scheduled for February 22, could change Fury, and Wilder's, position on this list.
Championships won: Three heavyweight world titles (2015).
=T 12: Deontay Wilder — 42 wins (41 knockouts) against one draw.
Weight class: Heavyweight.
Nationality: American.
Why he's ranked: Just looking at Wilder's record bring two words to mind — holy hell.
Only two of his opponents have heard the final bell, and only one, Tyson Fury, left the ring with a draw.
Wilder has fought 42 times and he has either knocked down, or knocked out, every opponent he's ever faced as a pro fighter.
The 34-year-old has power like no other in boxing today. It is a brutal, one-punch, knockout power that ends a fight at a moment's notice.
Wilder can be losing every minute of every round of a fight, like he was in his rematch with Luis Ortiz in November, before ending the bout with his mighty right hand.
That's scary power, and an incredible asset to brag about.
Championships won: WBC heavyweight title (2015 to present).
10: Josh Taylor — 16 wins (12 knockouts), unbeaten.
Weight class: Super lightweight.
Nationality: Scottish.
Why he's ranked: The 28-year-old southpaw is one of three fighters on this list who have benefitted from participating — and winning — the prestigious World Boxing Super Series (WBSS) competition.
The WBSS has one mission whenever it organizes an eight-man competition — bring the best fighters in one weight class into one tournament, and make them box each other in a knockout format until there's only one man left standing.
That man in the 2018-2019 super lightweight edition was Josh Taylor, who knocked out the American athlete Ryan Martin in last year's quarterfinal before defeating Ivan Baranchyk and Regis Prograis to claim the Muhammad Ali trophy this year.
The win over Prograis is a leading candidate to win the Fight of the Year, and as Taylor won, it is something that gives him a great platform going forward.
Championships won: Two super lightweight world titles (2019 to present).
9: Gennady Golovkin — 40 wins (35 knockouts) against one loss and one draw.
Weight class: Middleweight.
Nationality: Kazakh.
Why he's ranked: The man who popularized the phrase "Big Drama Show" plays his part in an event like few others.
Before Golovkin turned professional, he was a wildly decorated amateur fighter with a 2003 World Amateur Championships gold medal and a silver at the 2004 Olympic Games.
He turned pro two years later, won his first (interim) world title four years after that, and quickly developed a reputation because of his punching power.
The only blemishes on Golovin's record are a 2017 draw against "Canelo" Alvarez, which some say he should have won, and a loss in the rematch, which he also should have won, according to others.
He recaptured a middleweight belt in his last fight, a close decision win over the Ukranian boxer Sergiy Derevyanchenko.
Championships won: IBF middleweight world title (2019 to present), and a former three-belt middleweight world titlist.
8: Juan Francisco Estrada — 40 wins (27 knockouts) against three losses.
Weight class: Super flyweight.
Nationality: Mexican.
Why he's ranked: Estrada has been a pro fighter for 11 years and, in that time, has already won world titles in three weight classes just like previous Mexican greats Julio Cesar Chavez, Erik Morales, and Fernando Montiel.
Estrada has signature wins over Brian Viloria in China, Giovani Segura in Mexico, and Srisaket Sor Rungvisai in California.
As a Mexican boxer, he naturally has a good left hook to the body, a solid right hand over the top, and good finishing instincts.
At 29, Estrada is, in theory, in his prime years as an athlete and as a fighter, and, with the backing of Matchroom Boxing and DAZN, could secure even more legacy wins in the near future. A trilogy bout against the former pound-for-pound fighter Sor Rungvisai (as the rivalry is currently tied at one win apiece) has been mooted.
Championships won: WBC world super fly title (2018 to present), and world titles at fly (2013 to 2015), and light fly (2012).
7: Manny Pacquiao — 62 wins (39 knockouts) against seven defeats (three knockouts) and two draws.
Weight class: Welterweight.
Nationality: Filipino.
Why he's ranked: Why wouldn't he be ranked?
Of all the fighters on this list, Pacquiao — a pound-for-pound mainstay for longer than his rivals here have been fighting for pay — needs no justification.
Championships won: WBA welterweight world title (2018 to present), and world titles at welterweight (2016, 2013 to 2014, 2009 to 2011), super middleweight (2010), super lightweight (2009), lightweight (2008), super featherweight (2008), super bantamweight (2001 to 2003), and flyweight (1998 to 1999).
6: Errol Spence Jr. — 26 wins (21 knockouts), unbeaten.
Weight class: Welterweight.
Nationality: American.
Why he's ranked: Since Floyd Mayweather retired for the third time after he finished the UFC fighter Conor McGregor in 2017, boxing has looked at the next great welterweight who can fly the flag for the sport, and also for America.
Spence Jr. is one of the American welterweights who could be that new dominant force, and few come cooler as he seems unfazed when standing face-to-face with whatever opponent, unflappable in the midst of leather-strewn battle, and has come up trumps in every bout.
He is an extraordinary in-fighter who possesses a good box of tricks and is capable of fighting at great pressure.
Spence Jr. has big wins over many top fighters including Kell Brook, Mikey Garcia, and Shawn Porter, but there is one rival he needs to beat to elevate his standing as a pound-for-pound athlete — and he's the next fighter on this list.
Championships won: IBF welterweight world title (2017 to present) and WBC welterweight world title (2019 to present).
5: Terence Crawford — 35 wins (26 knockouts), unbeaten.
Weight class: Welterweight.
Nationality: American.
Why he's ranked: To watch, the switch-hitting Crawford appears to be the most beautiful boxer on the planet.
He's got fast hands, good counter-punching ability, and solid defensive skills.
His achievements as a three-weight world champion and the undisputed king of the light welterweight division also puts him in good stead in this list. But he doesn't rank higher because Crawford has no clear, career-defining victory.
Signed to the Top Rank promotional stable, Crawford's main rivals — Pacquiao and Spence Jr. — are currently signed to the rival fight firm Premier Boxing Champions. Crawford needs to fight at least one of those PBC athletes, preferably both, and win, if he wants to climb higher as a pound-for-pound force.
Championships won: Current WBO welterweight world title holder as well as the former undisputed light welterweight champion and the WBO lightweight titlist.
4: Naoya Inoue — 19 wins (16 knockouts), unbeaten.
Weight class: Bantamweight.
Nationality: Japanese.
Why he's ranked: A fighter who has benefitted from a popularity explosion after his participation in the 2018-2019 bantamweight edition of the WBSS, Inoue scored a stoppage over Juan Carlos Payano in the 2018 quarterfinal, beat Emmanuel Rodriguez in the 2019 semifinal, and engaged Nonito Donaire in a Fight of the Year type bout in November's final.
Inoue is now the best bantamweight boxer in the world, having previously won world titles at junior bantamweight and light flyweight. After beating Donaire at the Super Arena in Saitama last month, Inoue signed a multi-year deal with the Las Vegas boxing promoter Top Rank.
ESPN reported that the contract "will bring Inoue to the United States to fight on ESPN platforms in early 2020."
WBSS promoter Kalle Saulerland, though, would not be surprised to see Inoue return to his groundbreaking tournaments, perhaps in a different weight class. "Maybe we'll see him in another weight class at the WBSS," Sauerland told Business Insider. "I'm sure he'll go up and through the weights and win more world titles."
Championships won: WBA bantamweight world title (2018 to present) and IBF bantamweight world title (2019 to present), ahead of world titles at junior bantamweight and light flyweight.
3: Oleksandr Usyk — 17 wins (13 knockouts), unbeaten.
Weight class: Heavyweight.
Nationality: Ukrainian.
Why he's ranked: A 2012 gold medalist at the Olympic Games in London, Usyk turned professional the following year, and won his first world title in his 10th bout — a decision win over Krzysztof Glowacki in Poland.
Usyk is a true world champion; he wins world titles on the road, defends them in another foreign territory, and has never lost. He takes on all-comes, and wins. In 2018, he unified all the major world titles when he won the cruiserweight edition of the 2017-2018 WBSS season, bringing to an end his time in the 200-pound weight class.
During that period, Usyk collected wins that look even better with time, including victories over Murat Gassiev, Mairis Briedis, and Marco Huck in the WBSS tournament. He has also beaten Michael Hunter and Tony Bellew before beating Chazz Witherspoon at heavyweight.
Usyk has been sparring Wladimir Klitschko this year and Business Insider understands the former long-reigning heavyweight king is a big fan of his countryman's technical abilities, and believes he can go far in boxing's glamour division.
Championships won: Former undisputed cruiserweight world champion.
2: Vasyl Lomachenko — 14 wins (10 knockouts) against one loss.
Weight class: Lightweight.
Nationality: Ukrainian.
Why he's ranked: If you don't like boxing after watching a Vasyl Lomachenko fight, then you never will.
Lomachenko is hailed as one of the best amateur boxers of all time as he fought 397 times, lost once, but beat the guy who beat him twice for good measure. He finished his amateur career as a two-time World Amateur Champion and a two-time Olympic champion.
He turned pro in 2013, fought for a world title in his second fight and, though he lost, won a world title in his third. He has fought in championship bouts ever since.
A human-highlight reel compared to Neo from The Matrix, Lomachenko is as athletic and technically-adept as they come — reminscent of the awesome Roy Jones Jr. in the 1990s.
He has already beaten Gary Russell Jr., Guillermo Rigondeaux, and Jorge Linares, but, at 31, it could be a case of the best being yet to come.
Championships won: Current three-belt lightweight title holder, after winning titles at junior lightweight and featherweight.
1: Saul 'Canelo' Alvarez — 53 wins (36 knockouts) against one loss and two draws.
Weight class: Middleweight, super middleweight, and light heavyweight.
Nationality: Mexican.
Why he's ranked: If weight classes were a dart board, you could drink a few beers, put on a blindfold, and throw an arrow, and chances are you'd hit a weight class that "Canelo" holds a championship belt in.
Alvarez only has one official loss on his record, a 2013 defeat to Floyd Mayweather when he was a light middleweight champion at 23 years old.
In the years since, "Canelo" has beaten Miguel Cotto, Daniel Jacobs, and Sergey Kovalev, and holds a disputed two-fight rivalry win over Gennady Golovkin.
Alvarez is so good, he could fight pretty much anyone at middleweight, super middleweight, and light heavyweight, and win — something he is proving right now.
Championships won: Simultaneous champion of two weight classes, as well as world titles at light heavyweight and junior middleweight.