The value of the deal for the Wigan mobile crane hirer was not disclosed, but it also coincided with a separate agreement for a £105m financing facility at Ainscough to support its four-year growth plan.
The Ainscough family sold the business in 2007 to the now defunct Bank of Scotland Integrated Finance for £255m.
Since then the firm has been hit by the downturn and last July posted a £70m loss prompting the need to strengthen the firm’s balance sheet.
Goldman Sachs and TPG have purchased Ainscough from Caird Capital, which is a joint venture between Lloyds and Coller Capital.
Neil Partridge, managing director at Ainscough, said: “The TPG and Goldman Sachs partnership brings extensive experience in the sector to Ainscough.
Our new owners are extremely resourceful and they will encourage our strategic thinking to further develop and grow the business.”
He added: “The restructuring of our balance sheet sees the group with a more appropriate capital structure and one that can more than support the growth and business objectives in the medium and longer term.
The new assets based lending facility from Burdale Financial, GE Capital and RBS Invoice Finance recognised the strength of the Ainscough business and the quality of its asset base, said Partridge.
“The new facilities will enable us to continue with our strategic aim to increase market share and extend our market leading position as new opportunities in the Energy and Renewables sectors continue apace.”