As many ill fated politicians have learned over the years, mission creep is an often inevitable outcome of any attempt to solve a geopolitical crisis by military means. The same unintended expansion can often occur with tax legislation – although not necessarily with the same political consequences. As governments grow increasingly desperate to finance ever increasing public service, health care and pensions costs – not to mention security requirements – taxes can multiply like spores in a cell tray. Fuel and alcohol excise taxes are one prominent example. VAT is another.

This kind of contagious taxation is what has the European financial service and banking sector worried when it comes to the pending EU Digital Service Tax. Eight months after the European Commission made the DST proposal groups such as the Association for Financial Markets Europe (AFME), the European Banking Federation (EBF), the Federation of European Security Exchanges (FESE) and others have realized they could easily be snared by the 3 percent DST. That’s because the scope of the DST, which is supposed to be temporary – would apply to intermediate “multi-sided digital interfaces.”

While the original intention of DST scope (when it comes to intermediate digital platforms) is to target companies such as Uber, Ebay, Airbnb and – to a lesser extent Amazon – the financial service and banking industries also use digital platforms for buying and selling services. These include trade execution services including providing liquidity, currency spot trading, settlement and clearing and others in order to offer a kind of one-stop-shop service.

As a result, the groups have launched a furious campaign to – as the EBF recently put it in a Nov. 16 letter to EU presidency holder Austria holder – make sure their services are “future proof” when it comes to the DST.“If a DST were introduced in the EU as an interim measure, then a clear exemption must be provided not only ad hoc for payments, trading venues or crowdfunding but for all types of financial and banking services,” the EBF said in the letter.

To ensure it has a DST blanket exemption the EBF insisted that all financial services listed in the EU Capital Requirements Directive should be exempt in order to “avoid any legal uncertainty and ensure that it is future-proof.”

Based on the pending proposal companies that sell online targeted advertising or use intermediary platforms or sell user ID data that have a 750 million euro or more annual global turnover and 50 million euros of EU sales would have to pay the 3 percent DST. In order to ensure it gets a blanket exemption, the EBF called for the terms of the scope to be adjusted.

“The EBF recommends that the calculation of the thresholds should only take into account the activities and commissions targeted by the taxation and not the global turnover of companies,” the EBF said.

To its credit the United Kingdom has adopted a digital service tax proposal that is more targeted and would avoid drawing in services that were not originally targeted. That is because the scope states specifically that search engines and social media (i.e. Facebook) would be targeted.

Without the financial service exemptions, the AFME, FESE along with the Swiss Finance Council (UBS and Credit Suisse), the European Association of CCP Clearing Houses, the European Federation of European Traders and others insist that double taxation will result.

“This will disregard the tax contributions already made by the service providers,” groups said. “It will also affect the international competitiveness of EU participants in trade venues, other financial market infrastructure and services providers.”

The groups ended the letter warning that the EU goal to establish a Capital Markets Union – a top priority of the current European Commission – where investment funds can be move seamlessly throughout the EU in order to boost economic growth will be in jeopardy.

“The important political objectives of the Capital Markets Union initiative should not be impaired via unintentional consequences of the DST,” the letter said.

In other words, the EU banking and finance service industry have a simple message to EU finance ministers: please avoid mission creep.