The idea that U.K. banks, especially investment banks, will suffer badly because of the Brexit vote is accepted by almost everybody, and the latest noises coming from various officials and experts have reinforced this view. But what if it's not all doom and gloom?

On the negative side of the balance, European Union officials keep saying that it is impossible for the U.K. to reach a good deal with the European Union. Donald Tusk, the president of the European Council, said in a speech on Thursday that it would be an "illusion" for Britain to believe that it can "have its cake and eat it," as U.K. Foreign Secretary Boris Johnson had promised during the Leave campaign.

"The brutal truth is that Brexit will be a loss for all of us. There will be no cakes on the table. For anyone," Tusk said.

Also on Thursday, French Finance Minister Michel Sapin said in a press conference that executives from major U.S. banks have told him they were looking to move some operations from London to another EU city. (On that note, our sister publication The Deal has a very good article on how France is wasting no time in luring companies away from the U.K. to its financial hub in Paris) 

The U.K. Investment Banks/Brokers sector has lost more than 15% year to date; it crashed by around 75% between June 23, the day of the vote, and June 27, according to FactSet data.

But for brave investors looking for bargains, this is a very good time to start going through the rubble. For one, the pound's sharp devaluation has made these shares incredibly cheap (with the caveat that the pound can always go lower and probably will, so they may get cheaper still).

More important, however, is a piece of news that among the Brexit noise has gone almost unnoticed. Ten EU countries reached agreement at the beginning of the week on some concrete measures to impose a tax on financial transactions. This is negative for the EU and positive for the U.K.

The issue first was posed by France and Germany in 2011 in order to force financial sector institutions to return some of the taxpayer money used to bail them out in various forms in the wake of the financial crisis. It was formally proposed by the European Commission in February 2013 and has been in discussions ever since.

French newspaper Les Echos reported that a judicial proposal on the main points of the agreement is being prepared and could be made public in December. The 10 countries are Germany, France, Italy, Spain, Austria, Belgium, Greece, Portugal, Slovakia and Slovenia.

Needless to say, this tax is unpopular among the governments of countries relying on big financial sectors. It can be argued that France, Germany and Italy also have big financial sectors, but in these countries financial services firms have not been historically considered as important for the economy as they are in Britain.

The U.K. had already had opted out of the financial transactions tax. Investment banks seeking to avoid paying this tax could try moving to Luxembourg or Dublin, two of the European locales preferred by bankers, besides Frankfurt, Paris or Vienna. But the bigger states in the EU could insist, in time, that the tax be paid everywhere.

Once this tax becomes reality, it will give a competitive advantage to U.K.-based investment banks and brokers because they will not be forced to pay it.

Investors seeking exposure to the sector should start their search with Investec, a wealth manager listed on the London Stock Exchange. It does not have an ADR, so U.S.-based investors need a European broker to access it (alternatively, it is also listed in South Africa). Investec is projected to see earnings and dividend growth over the next two years, and analysts have a target price of £5.63 on it, a nearly 20% upside from the current level.

Another London-based broker worthy of a look is ICAP (IAPLY) , an interdealer brokerage firm that also provides post-trade risk and information services. This one does not come cheap, though: its price-to-earnings multiple on a forward 12-month basis is still above its five-year average based on FactSet data about the London-listed security, which is more liquid than the ADR.

Schroders, an investment manager listed only in London, is another company that investors should check out. Year to date, the share price has lost more than 7%, but it has an average rating of overweight from the 18 analysts covering the stock. The company has been increasing its net margin every year since 2012 and has a decent dividend yield of 3.1%, according to data from FactSet.

Editor's Note: This article was originally published on Real Money at 9 a.m. on Oct. 14.

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