United were fined $335,000 for failing to meet the break-even requirement that attempts to limit the losses made by clubs.
Barcelona and Manchester United were among the clubs fined by UEFA on Friday for breaches of financial fair play (FFP) regulations during the 2022/23 season.
United were fined 300,000 euros ($335,000) for failing to meet the break-even requirement that attempts to limit the losses made by clubs.
Spanish champions Barcelona was hit with a 500,000-euro sanction for including profits from sales of intangible assets, which are not relevant income under the regulations, to balance their books.
FFP rules, which were introduced in 2010, have allowed clubs to report losses of no more than 30 million euros over a three-year period.
Last season was the final year those regulations will be used by UEFA before new licensing and sustainability regulations are eased in over the next three seasons.
Champions League finalists Inter Milan, AC Milan, Paris Saint-Germain, Monaco, Roma and Marseille escaped sanction after meeting targets set by a UEFA settlement agreement.
Belgian club Royal Antwerp and Turkish side Trabzonspor were hit with the biggest fines of two million euros each.