London capital markets partners are anticipating a flurry of initial public offerings (IPOs) this year, ahead of the UK's exit from the European Union in 2019.

Partners says there is an impetus to start IPO processes early in order to avoid any uncertainty in the run-up to Brexit, scheduled for 29 March next year.

Clifford Chance (CC) global capital markets head Adrian Cartwright (pictured above) comments: "Most companies are looking to get IPOs away in 2018, as the first half of 2019 will be overshadowed by Brexit. You really need to be getting a process underway in the next two to three months to hit an execution window in the second half of 2018."

White & Case partner Jonathan Parry (pictured right) adds: "There is definitely a pre-Brexit window to aim for. A number of IPOs are expected to hit the early summer window."

With Brexit looming, partners say the volume of deals will at least match 2017. Last year, there were 106 IPOs raising a total of £15bn in London, a three-year high – a strong increase on 2016, which saw 65 IPOs raise £5.7bn.

If you haven't got a deal done by the end of the third quarter, you will be getting into a nervous period

Key IPOs in 2017 include the Irish Government's May flotation of a 25% stake in Allied Irish Bank, which valued the group at €12bn (£10.5bn). The dual-listing in London and Dublin threw up roles for Linklaters, Allen & Overy and Herbert Smith Freehills.

Meanwhile, in November, Russian aluminium company EN+ floated in London and Moscow, giving the overall business a value of $8bn (£5.6bn). It was the first major primary listing by a Russian company in London since sanctions were imposed on Moscow. White & Case acted for EN+ and Linklaters advised the banks.

In April, logistics company Eddie Stobart raised £393m on AIM, the largest AIM IPO since 2005. King & Spalding acted for Eddie Stobart while Hogan Lovells advised the banks.

Ashurst partner Nicholas Holmes comments: "I think 2018 could be broadly comparable to 2017, but my suspicion is that activity in 2018 will be compressed into three rather than four quarters. If you haven't got a deal done by the end of the third quarter, you will be getting into a nervous period as Brexit becomes more imminent."

Parry adds: "Overall volumes could be higher this year. Last year, volumes in the first half were pretty low in terms of premium listing IPOs and it was a very sluggish market. There was a change post-summer – the IPO pipeline picked up considerably in Q3, and as a result overall volumes for the 2017 were fairly high."

At the same time, some companies may opt to take their chances in a less crowded market in early 2019, comments Allen & Overy partner James Roe (pictured right). "There's an impetus to get transactions done before October 2018, but equally if the market is crowded as a consequence there may be opportunities towards the end of this year or the first quarter of 2019 for a prepared company to IPO."

By region, partners say the London listings are expected to come from a range of locations including Turkey – spurred on by general elections in the country scheduled for November 2019 – Greece and the Middle East.

Cartwright comments: "There is activity across a whole mix of jurisdictions, including the UK, continental Europe, Turkey, and Russia is also back, despite the threat of further sanctions. The Middle East is also busy."

Herbert Smith Freehills equity capital markets head Charles Howarth adds: "There are some UK IPOs of non-UK companies, but much of the IPOs are from the far end of the Mediterranean, Turkish and Greek. There is a burgeoning pipeline of Turkish IPOs, both domestic and London, driven in part by uncertainty over the elections due late next year."

Much talk in the market is dominated by the potentially record-breaking Saudi Aramco IPO, which could value the company at as much as $2.5trn (£1.7trn). It is understood the company has shortlisted London, New York and Hong Kong for the international portion of the listing. It is understood that White & Case is acting for Saudi Aramco, but further legal advisers have yet to be appointed.

Other IPOs that could launch this year include UK cinema chain Vue Cinema International, which would reportedly value the group at at least £1.6bn, while its rival Odeon is also looking at a listing of a similar value.

Overall, companies and investors seem more likely to take their chances sooner rather than later.

Parry concludes: "There is still very little clarity as to what is going to happen in March 2019. At the moment, with investor sentiment and stock market valuations where they are, there does seem to be an open window that issuers and investment banks are looking to take advantage of."