ViiV Healthcare could generate one of the biggest IPOs in history, if GSK decides to go ahead and make it a spin-off company.
The pharmaceutical firm was created in 2009 as a joint venture between GSK and US firm Pfizer. It specialises in developing therapies for HIV and operates in 16 countries.
With revenues at £1.03bn and operating profit at £675m during the first nine months of 2014, it is thought that ViiV could be valued at up to £15bn, making it bigger than M&S and Sainsbury's combined.
Its most recent HIV medicines, Trumeq and Tivicay, became available in the last year as "one of the most successful new product launches in the category,” according to chief executive Sir Andrew Witty.
Past spin off success stories
If the spin off goes ahead and is successful, it could join ranks with the following companies, all of which gained great success after flying their parent company nests.
Spun off from Marathon Oil Corp in June 2011, its first-quarter dividend soon increased by 25 per cent. Low crude oil prices helped to bring up margins, and the company's 2012 revenues went up by 6.5 per cent. With lots of free cash available, it remains an attractive prospect for investors.
The $36bn snack food company Mondelez was spun off by Kraft Foods. Major brands under the Mondelez umbrella include Oreos, Ritz and Trident. The first quarter following the split was not easy, with snack revenues going down by two per cent. But it soon started to perform well, reaching double-digit revenue growth in a matter of months.
The defence contractor and military shipbuilder was spun off from Northrop Grumman in March 2011. Northrop made the move so that it could concentrate on information systems, aerospace and technical services. Initially, Hntington Ingalls did not perform as well as investors hoped because of the damage caused by hurricane Katrina to some shipyards in Mississipi and Louisiana.
But once the company had closed down some poorly performing facilities and won a ship rebuilding contract worth £2.6bn from the US Navy, revenues started to grow.
Spun off from consumer goods corporation Sara Lee in 2012, HillShire Brands quickly benefited from the strong performance of brands such as Ball Park hot dogs and Jimmy Dean sandwiches. Stock rose sharply after the split, delivering a premium of more than 15 per cent to shareholders. The baked goods and beverages division left behind was rolled into the D.E. Master Blenders 1753.
Phillips 66 was spun off by refining company ConocoPhillips. A drop in crude oil prices and an increase in refiners' margins allowed earnings to reach $5.4bn in 2012, up from $3.6bn the year before. This meant Phillips 60 could return $400m worth of capital to its shareholders in 2012, through dividends and share purchases.