维护欧元区金融稳定的过程中，黑社会、贩毒集团和洗钱团伙似乎正在尽他们自己的一份力。
据有关部门说，这缘自于他们对高面值欧元纸币的需求，特别是对200欧元和500欧元面值纸币的需求。在欧洲央行(European Central Bank)应对金融危机的行动使其财务实力出现问题之际，它发行这些钞票得到的巨额利润真好比雪中送炭。
花 旗集团(Citigroup)首席经济学家布伊特(Willem Buiter)最近撰写研究报告说，由于这些高面值钞票的存在，黑市及所有在财务交易或投资中喜欢匿名的人都越来越喜欢选用欧元。他写道，纸币的生产成本 几乎为零，发行欧元纸币的业务让欧洲央行“获得了可观的利润”。
欧洲央行的数据显示，2002年1月份欧元纸币和硬币进入流通之时，500欧元纸币的流通量为308亿欧元（合400亿美元）。
目前存在的500欧元纸币约为2,850亿欧元，每年增长32%。按价值计算，流通的欧元纸币当中有35%都是很少有人见过的最高面值纸币，即500欧元纸币。
总部位于海牙的欧洲警察组织(Europol)发言人彼得尔森(Soren Pedersen)说，警察在麦片盒、轮胎和卡车隐蔽隔间里都曾发现大面值欧元纸币。他说，不用说，这些现钞常常跟非法毒品交易有关，这可以解释所用隐藏手段的相似性。
欧洲央行一位发言人拒绝就谁使用这些纸币置评。欧洲央行及其成员国政府都是这种需求的受益者。
央行从发行货币和其他特权（如有权要求银行在央行低息或无息存款）获得的利润被叫做“铸币税”(seigniorage)。一旦央行需要解释自己的成本，铸币税通常就被算入国库。
今年，欧洲央行从铸币税中获得的利益正变得越来越重要。
在应对全球金融危机的过程中，欧洲央行将数千亿欧元不明质量的资产放进了自己的资产负债表。
它持有价值在6,000多亿欧元的给银行贷款时获得的质押品，并直接持有包括国债在内的4,000多亿欧元证券。
欧洲央行资产负债表总额已增至近2万亿欧元，资本金基础为780亿欧元。布伊特在报告中说，由此形成的杠杆率，使欧洲央行看起来像一只“打了激素的对冲基金”。这些资产不需要有多少亏损就足以冲破它微薄的资本缓冲。
铸币税就在这里发挥作用。
近些年，欧洲央行发行新纸币的利润一直在500亿欧元的水平。在雷曼兄弟(Lehman Brothers)倒闭的2008年，利润为800亿欧元。
布伊特估计，即使对未来的流通货币增长速度做保守估计，比如每年增长4%，也就是欧洲央行2%通胀目标加上2%的经济增长率，欧洲央行未来铸币税利润也会在2万亿欧元到6.9万亿欧元之间。
他说，由于铸币税的存在，欧洲央行的还债能力“超强”。
欧元诞生以前，有六个成员国曾经使用各自的高面值纸币。欧洲央行一位发言人说，央行没有打算回收高面值纸币。未来几年发行一组新设计的纸币系列的时候，高面值纸币仍将保留。
她说，用小面额纸币来取代它们会增加生产和处理成本。
Gangsters, drug dealers and money launderers appear to be playing their part in helping shore up the financial stability of the euro zone.
That is thanks to their demand, according to authorities, for high-denomination euro bank notes, in particular the 200 euros and 500 euros bills. The European Central Bank issues these for a hefty profit that is welcome at a time when its response to the financial crisis has called its financial strength into question.
The high-value bills are increasingly 'making the euro the currency of choice for underground and black economies, and for all those who value anonymity in their financial transactions and investments,' wrote Willem Buiter, chief economist at Citigroup, in a recent research report. The business of issuing euro notes, produced at almost zero cost, is 'wildly profitable' for the ECB, Mr. Buiter wrote.
When euro notes and coins went into circulation in January 2002, the value of 500 euros notes outstanding was 30.8 billion euros ($40 billion), according to the ECB.
Today some 285 billion worth of such euro notes are in existence, an annual growth rate of 32%. By value, 35% of euro notes in circulation are in the highest denomination, the 500 bill that few people ever see.
Police forces have found the big euro notes in cereal boxes, tires and in hidden compartments in trucks, says Soren Pedersen, spokesman for Europol, the European police agency based in The Hague. 'Needless to say, this cash is often linked to the illegal drugs trade, which explains the similarity in methods of concealment that are used.'
A spokeswoman for the ECB declined to comment on who uses the bills. The ECB and its member governments are beneficiaries of the demand.
The profit a central bank gains from issuing currency -- as well as from other privileges of a central bank, such as being able to demand no-cost or low-cost deposits from banks -- is known as seigniorage. It normally accrues to national treasuries once the central banks account for their own costs.
The ECB's gains from seigniorage are becoming increasingly important this year.
The ECB has taken hundreds of billions of euros of assets of unknown quality on to its balance sheet as it has reacted to the global financial crisis.
It holds more than 600 billion euros in collateral from banks to which it has made loans, and more than 400 billion euros in securities it holds outright, including government bonds.
Overall, the ECB's balance sheet has grown to almost 2 trillion euros. It has a capital base of 78 billion euros. That creates leverage that makes it look like a 'hedge fund on steroids,' Mr. Buiter wrote. It wouldn't need to lose much on these assets to wipe out its thin cushion of capital.
That is where seigniorage comes in.
In recent years, the profits on its issue of new paper currency have been running at 50 billion euros. In 2008, the year of the Lehman Brothers crisis, it was 80 billion euros.
Even with conservative assumptions about future growth of currency in circulation -- at, say, 4% a year, which is in line with the ECB's 2% inflation target plus a margin for economic growth -- Mr. Buiter estimates future seigniorage profits for the central bank between 2 trillion euros and 6.9 trillion euros.
Thanks to seigniorage, he says, the ECB is 'super solvent.'
An ECB spokeswoman says there is no plan to withdraw high-value notes, national equivalents of which were used in six member states before the euro was launched. They will be retained when a redesigned series is issued in coming years.
Replacing them with small denominations would increase production and processing costs, she says.