Many investors will have banked that gain, but others are sitting tight for the long-run.
Historically, privatisations have been plagued with a number of ills, yet many of these businesses have come out the other side stronger for it and literally paid dividends to shareholders over the long-term.
Margaret Thatcher, the force behind the large-scale privatisation of state-owned assets, once said: "Privatisation shrinks the power of the state and free enterprise enlarges the power of the people."
This may or may not be true, but what about what it does to our wallets? Here FE Trustnet looks at three of the most successful privatisations in British history.
The lesson for Royal Mail shareholders seems to be that it could take some time for their investment to prove successful.
Rolls-Royce
Anyone who bought shares in the initial public offering of Rolls-Royce in 1986 would have had to have waited a long time to reap the rewards.
It floated at 170p per share. In August 1995, at the start of FE data, the share price of Rolls Royce sat at 180p, a mere 5.9 per cent higher than it had been nearly a decade before.
By the turn of the century the firm was under threat of being booted out of the FTSE 100 after it reported a slump in profits for the first half of the year.
In mid-2000, the share price plummeted more than 22 per cent to 169.5p, just below its initial float price. The share price fell even further in March of 2003, down to just 64.25p per share.
However, investors who stuck with the aerospace engineering firm would have seen their returns skyrocket from then on.
Since its lowest point on 27 March 2003, Rolls-Royce has rallied by nearly 2,000 percentage points, picking up 1,957.25 per cent, according to FE Analytics.
The FTSE 100 index made just 162.53 per cent over this period.
Performance of stock vs index since Mar 2003
Source: FE Analytics
Investors who held the stock all the way from its launch in 1986 through the tumultuous 1990s and early 2000s would have seen their initial investment grow from 170p per share to 1,139p per share.
This means that an initial investment of £1,000 in Rolls-Royce would be worth roughly £6,700 today. Rolls-Royce has a 2 per cent yield, which is expected to increase to 2.3 per cent next year.
The stock is a top-10 holding in 31 funds in the IMA universe, including the BlackRock UK and UK Absolute Alpha funds and Newton UK Equity.
BP
Another industrial giant that was formerly publicly owned is mega-cap oil firm BP. Much like Rolls-Royce, the firm has been plagued with bad news over the years, but has continued to deliver strong share price growth and an income to investors.
The firm was initially launched into the public sphere in 1977 under Jim Callaghan’s Labour government, but the bulk of the firm was sold off throughout the 1980s.
Investors in the 1987 public offering would have been able to grab the shares at 330p; they are now trading at 449.8p.
While investors would certainly have made money picking up BP, the firm hasn’t fared as well as others in the FTSE 100 since the start of FE data in 1995.
BP shares have gained 237.82 per cent over this period while the index has picked up 261.15 per cent.
Performance of stock vs index since 1995
Source: FE Analytics
BP’s underperformance stems from April 2010 and the infamous Deepwater Horizon disaster which left the company with huge legal bills and caused the share price to more than halve.
The spill was the largest in the history of the oil industry and left BP saddled with a poor reputation and liable for compensation to those affected.
However, since the stock hit its low point on 26 June it has rebounded strongly, gaining 66.48 per cent, more than 15 percentage points ahead of the FTSE 100 during that period.
BP is currently yielding 5.1 per cent, which is expected to rise to 5.6 per cent next year.
The stock is a staple in more than 300 funds and investment trusts in the UK, including FE Alpha Managers Adrian Frost and Adrian Gosden’s Artemis Income fund and the five crown-rated Trojan Income fund, headed up by FE Alpha Manager Francis Brooke.
British Airways
Much like the privatisation of Royal Mail, the flotation of British Airways was massively oversubscribed, with more than one million people vying to purchase a chunk of the airline in 1987.
The firm floated at 65.5p and the share price spiked by more than 80 per cent on the first day of trading.
British Airways merged with Spanish airline Iberia in 2010, creating the massive International Consolidated Airlines Group which is now known as IAG. Shares in the combined firm were trading at 364.9p at the time of writing.
Investors who have held the stock since it floated would be looking at gains of nearly £3 per share.
However, investors would have had to have waited to see the company outperform its underlying index since the merger. Iberia has proved to be a troubled company, with industrial disputes piled on top of operating losses, making it an albatross around BA’s neck.
Shares in the company lagged the FTSE 100 until this month, when the share price jumped ahead of the index by just shy of 1 percentage point.
Performance of stock vs index since 2010
Source: FE Analytics
IAG does not currently have a dividend but it is expected to pay out a meagre 0.1 per cent at the end of next year. This is expected to increase to 0.5 per cent at the end of 2014.
Thirteen funds in the IMA universe hold the stock in their top-10, including the CF Odey Continental European fund and the Schroder UK Alpha Plus portfolio, previously run by Richard Buxton.