This weekend, the men’s and women’s singles champions at the United States Open will take home at least $1.8 million each. The total prize money is a record $23.7 million. The tournament’s revenue is expected to exceed $200 million.

Gold badge chair umpires, the highest-rated officials in professional tennis, the ones who work the most important tournaments and matches, make $250 each day at the Open. It is the lowest pay rate for any Grand Slam tournament. There are 26 such umpires. Twenty-four of them worked Wimbledon, but only 13 are here at the Open.

“We’ve been saying this for years and years,” Norm Chryst, a retired gold badge chair umpire, said Tuesday in a telephone interview. “The U.S. Open makes more and more each year, but very little of that goes to the officials. Gold badge umpires don’t want to come here. Why? A lot of the answer is money.”

For gold badge umpires, officiating tournaments is their primary job and main source of income. At most tournaments, their pay is set by the ATP World Tour, the WTA or the International Tennis Federation. But at Grand Slam events, tournament organizers dictate everything from pay rates to accommodations.