Josh Taylor’s first fight as boxing’s undisputed 140-pound champion might be his last.

The Scottish star appreciates what becoming just the fifth fully unified champ in any weight class during the four-belt era has done for his legacy. He respects the responsibility that comes with that distinction as well, yet Taylor also is a practical person.

The bottom line for Taylor is that retaining the IBF, WBA, WBC and WBO titles simply might become more expensive than it is worth. Taylor (18-0, 13 KOs) is set to pay 11 percent of his purse in sanctioning fees – 2 percent to the WBO and 3 percent apiece to the IBF, WBA and WBC – for his 12-round fight against England’s Jack Catterall (26-0, 13 KOs), the mandatory challenger for his WBO belt, on Saturday night at OVO Hydro in Glasgow, Scotland.

“It’s not easy because, you know, you’ve then got all the sanctioning fees,” Taylor told BoxingScene.com. “Each one takes a percentage, so there’s four sanctioning fees that you have to pay straight away off your paycheck. And then after this fight, which mandatory becomes another mandatory becomes another mandatory and rolls into another mandatory defense, from all the different organizations?

“So, it becomes quite hard to then keep hold of all the belts or chase the fights that you want because then you’ve got to deal with mandatories all the time. And that’s a whole lot of money you’re giving away out of your paycheck. It’s a big percentage of your paycheck you’re giving away to the sanctioning bodies. So, you understand why people move on from it or relinquish some of the belts.”

Taylor, of Prestonpans, Scotland, added the WBC and WBO belts to his IBF and WBA championships May 22. He defeated Jose Ramirez (26-1, 17 KOs) by majority decision that night in their 12-round, 140-pound title unification fight at Virgin Hotels Las Vegas.

The 31-year-old Taylor thinks there are “big fights” left for him within the 140-pound division. He mentioned Jose Zepeda (35-2, 27 KOs, 2 NC) and former unified lightweight champ Teofimo Lopez (16-1, 12 KOs) as potential opponents later this year, but a 147-pound showdown with WBO welterweight champ Terence Crawford (38-0, 29 KOs) probably appeals more to Taylor at this point because he wants to become a champion in a second division.

“All this goes back to the conversation we just had, and it becomes mandatory defense after mandatory defense,” Taylor said. “So, I’ve got nothing left to do at the weight category. I’ve achieved everything. The only thing left to do is defend the belts. If all goes my way [against Catterall], we’ll see what happens. I’m not making any decisions [before facing Catterall], because I still think there’s big fights at 140 to be had if I stay at the weight. You know, so yeah, I think the next natural thing would be to go up to welterweight. But if a big fight lures me in, keeps me there, I’ll probably stay [at 140].”

Sky Sports will air Taylor-Catterall as the main event of its telecast Saturday in the United Kingdom and Ireland (7 p.m. GMT). ESPN+ will stream this bout between unbeaten southpaws as the main event of a card scheduled to start in the United States at 2 p.m. ET and 11 a.m. PT.

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.