Sir Jim Ratcliffe initiated cost-saving measures after he became a minority owner of the club last year.
Last summer, around 250 staff were made redundant, saving the club an estimated £8m-£10m. A further 200 staff could lose their jobs this summer.
In March, United revealed plans for a new £2bn stadium on the site of Old Trafford.
Real top the rankings with a value of $6.75bn and revenue of $1.129bn, while Barcelona are third.
Manchester City boasted the second largest revenue in 23-24 ($901m), but are fifth in terms of total value ($5.3bn), a 4% rise on the previous year.
Liverpool are the fourth most valuable football club in the world with a value of $5.4bn) and a revenue of $773m in 23-24.
Forbes’ team valuations are enterprise values (equity plus net debt) based on historical transactions and the future economics of each league and each team.
Revenue and operating income – such as earnings before interest, taxes, depreciation and amortization – reflect the 23-24 campaign.
The team values include the economics of each team’s stadium but not the value of the stadium real estate itself.
Debt is measured in terms of interest-bearing borrowings due in more than one year (including stadium debt).
Forbes’ valuations came from club annual reports and documents, team executives, investors, credit rating agency reports and sports bankers.