Sirius, a company which former Ryanair Chief Financial Officer Howard Millar is head of, has postponed its IPO until later this year.
Industry sources had suggested that the company may have been forced to entirely abandon its move to raise capital for the aircraft leasing fund through an initial public offering (IPO).
The company was forced into delaying the flotation twice last year and now appears to have done so again.
"Due to continuing Brexit uncertainties and resultant market volatility, the IPO has been postponed until later in 2019," the company said in a statement to the Sunday Independent.
Sirius was due to launch on the London Stock Exchange in November 2018, with the company looking to raise at least $250m (€218m) from investors.
The company was targeting an 8pc dividend yield, and a total return target of an internal rate of return of 10pc.
Millar, who is still a non-executive director with Ryanair, has established Sirius with aviation executives Ed Coughlan and Ed Hansom.
The trio, who previously worked together at aviation-leasing group Stellwagen, took the decision to delay it until December but the group later postponed it until "early 2019".
The group was being advised by Liberum Capital and Davy, and had produced a prospectus on the proposed flotation to provide further information for investors.
After the trio left the company, Stellwagen took legal action against the executives in an effort to prevent them from allegedly planning to use "highly confidential material" to compete with Stellwagen.
The company claimed that the trio were behind unlawful and clandestine misuse and distribution of commercially-sensitive and highly confidential material acquired by them during their employment.
The three executives have denied all of the claims made by Stellwagen and its founder, Douglas L Brennan.
Sunday Indo Business