Bardsley Construction's Dave McEwan and Ted McDougal are raising funds for Help for Heroes after swimming across the English Channel.
Ian Shaw of M-tec and Nathan Royle of Barrett Dixon Bell joined them, who have all raised a total of £4,500 for the charity which supports members of the Armed Forces wounded in the service of their country.
Wayne Bardsley, chairman of Bardsley, promised to donate £1,000 if the team posed for a picture in their swimming trunks.
Following his kind gesture, although it is difficult to believe, Philip Treanor, a partner with Manchester-based law firm Pannone, then offered to match this sum if the team posed Speedo-less and the four businessmen agreed.
The four men took turns to swim across the English Channel, swimming for an hour each, and completed the challenge in 13 hours and 57 minutes in total.
McDougal, managing director of development at Bardsley, said: "We initially planned the swim to satisfy a longstanding ambition among four friends.
"But when the idea became a reality, friends, family and colleagues all offered to sponsor us so we decided to choose a charity and opted for the very deserving Help for Heroes.
"The fact that the 'cheeky' photo had the potential to generate £2,000 for the charity made the challenge of getting naked in Salford more than worthwhile."
Tameside-based Bardsley Construction has a £70m turnover and has retained its 213 staff and completed 130 consecutive projects within programme despite the economic downturn.
Barrett Dixon Bell is an independent, full-service trade and technical marketing communications consultancy.
M-tec is a single supplier for all of the technology of dry premixes, from raw materials to finished product, to construction industrials.