LONDON (Reuters) – Banks which are shifting operations to avoid disruption once Britain leaves the European Union hope only a handful of people will eventually have to leave London, industry sources say.

Wall Street’s Citigroup Inc. (C.N) and Morgan Stanley (MS.N) as well as Britain’s Barclays (BARC.L) have all in the last week indicated they are finalizing plans to set up subsidiaries within the EU.

Along with other banks, they are planning for a worst-case scenario as they say they do not have time to wait to see how Britain’s talks with Brussels unfold.

They are focused on ensuring they have the right legal and operational framework to do business in the EU if Britain fails to negotiate a favorable exit deal, banking executives say.

But they are holding off on implementing plans to move a significant number of people, cautious that some of their contingency plans may never need to be enacted.

A senior executive at one British bank told Reuters he was reluctantly spending a few hundred million pounds building a new EU base as cheaply and quickly as possible.

“It’s an insurance policy. I just have to figure out what the cheapest insurance policy is … in a perfect world, we will just tear it up,” he said.

The timetable for setting up EU bases and operations is tight because it could take longer than eighteen months to arrange office space, obtain licenses and build up capital.

And although Bank of England Governor Mark Carney asked them to show by July 14 how they can avoid clients being cut off after Brexit, banks are treading carefully, enacting two-stage contingency plans, to avoid losing nervous London-based staff and potentially unnecessary expenses.

The first phase involves moving relatively small numbers to make sure the licenses, technology and infrastructure are in place, while the next requires longer term thinking on what their European business will look like in the future.

If an exit deal is signed that allows, for example, euro-denominated trades to be booked at subsidiaries in the EU but executed from London, then the number of people who move in total could be fairly low.

“All banks will start from where they have the entity. It may not be where they end up. This has a 2nd or 3rd or 4th phase but you have to be ready by March 2019,” another senior banking source at an international bank said.

Reversible Moves

The largest global banks in London had indicated about 9,600 jobs could go to the continent in the next two years, public statements and information from sources shows, accounting for just over 2 percent of finance jobs in the City of London.

JP Morgan (JPM.N) CEO Jamie Dimon said before the Brexit vote last year that his bank alone might move as many as 4000 jobs if Britain left the EU, but so far banks have indicated only a fraction of that number are likely to go.

Citigroup executive Jim Cowles said in a memo to staff on Thursday that the bank may need to create around 150 jobs in the EU as a result of Brexit, but that was only in “certain circumstances” and depended on the outcome or timing of talks.

Sources at several large investment banks in London say no staff have as yet been moved, while some financial firms are contemplating how they can reverse any such decisions.

The “point of no return” is sooner the larger and more complex the institution, while customer and staff transfers are also key, Rachel Kent, partner at law firm Hogan Lovells, said.

“Some firms I’ve spoken to have explicitly said if there is a (favorable) deal they would reverse that,” Kent added.

One such example is Lloyd’s of London, the world’s largest specialty insurance market, which said in March that it had chosen Brussels as its EU subsidiary.

But Lloyd’s, which declined to comment, could reverse any changes should a “good” Brexit deal be struck, a source familiar with the matter said.

And Andrew Bailey, chief executive of the UK’s Financial Conduct Authority told Reuters in July that Britain and the EU are in a position to preserve free trade for financial services, meaning such moves need not happen.

However, Bob Jenkins, who served on the Bank of England’s Financial Policy Committee, warned many banks are using the threat or promise of moving to wrangle tax and rule changes.

“They will play this for all its worth,” Jenkins said.