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2011年8月30日 星期二

監管收緊 A股ETF要100%抵押品

合成交易所買賣基金(ETF)涉及複雜結構,多個市場的監管機構最關注這類產品的交易對手風險。證監會昨天公布,13隻A股合成ETF必須由100%的抵押品支持,如果以股票為抵押品,更要達到120%的水平,今年10月31日起實施。

證監會一直要求單一對手風險不能超過產品資產淨值10%,現在從抵押品方面着手。證監會署理行政總裁張灼華相信,提高抵押品水平,可更有效減輕本地合成ETF的交易對手風險。

根據新措施,本地合成ETF基金經理必須提高每隻本地合成ETF的抵押品水平,最少相等於ETF交易對手風險總額的100%,確保合成ETF為模擬指數表現而進行的所有金融衍生工具交易,均備有抵押品,從而抵銷交易對手風險。

證監會表示,相關合成ETF基金經理還要訂立審慎的抵押品扣減(haircut)政策,尤其是當抵押品屬於股本證券,這類抵押品的市值,要相等於交易對手風險總額120%。

以全球最普遍的抵押品美國國債為例,本月初標準普爾調低美國主權評級後,理論上其作為抵押品的價值便會下跌,收取抵押品的一方可能要求更多抵押品,或減低倉位水平。

證監會要求,基金經理於未來兩周後開始提高抵押品水平,並要在可行情況下盡快作出全數抵押安排,最遲須於10月31日前完成。

至今本港的ETF共76隻,實物資產和合成的ETF分別各佔27隻和49隻。不過,新措施只限於受證監會規管的本地合成ETF,僅13隻,全部屬於A股ETF,其餘36隻屬於在港跨境上市的海外合成ETF,則不受新措施影響。

本港最大ETF發行人之一的貝萊德,其安碩(iShares)亞太區主管高磊(Nick Good)回應說,集團將繼續利用多個交易對手,以分散這方面的風險,同時,各安碩基金的抵押品在獨立的保管賬戶上單獨保管。

目前ETF基金經理需要在產品網站披露整體抵押品水平和其他抵押品資料,配合新措施,合成ETF基金經理需要持續地在產品網站公布最新的抵押品管理政策。

2011年8月29日 星期一

Quant Fund 盟主不敗之謎



美國長期資本管理公司(LTCM)董事局的Myron Scholes和Robert C. Merton不但是1997年諾貝爾經濟學獎得主,直到目前市場仍然採用他們設計的方程式計算期權金。然而,LTCM成立短短6年便因為投資失敗而倒閉,使人懷疑數學理論只是紙上談兵;不過,同樣以數學及科學專才為骨幹的Medallion基金卻以連續20年保持雙位數回報而傲視群倫。


計量金融學或金融數學(Quantitative Finance或Mathematical Finance)是結合金融和數學的學科,運用高級數學原理例如機率微積分就投資產品包括證券的投資風險分析及定價,市場利用計量金融學模型進行程式買賣的基金(quant fund)比比皆是,但西蒙斯(Jim Simons)1982年創辦的Renaissance Technologies旗艦Medallion對沖基金的投資回報,所有對沖基金同業都無出其右,Medallion從1990至2006年扣除費用平均年回報高達38.5%,而1999至2007年底更創下每個季度全勝的驚人紀錄。

兩千多年前大思想家莊子說:一尺之棰,日取其半,萬世不竭;意思是一根一尺長的木杖,每天折去一半,木杖永遠也折不完。西蒙斯大約三歲時,有人告訴他當汽車用盡了汽油便不能行駛,西蒙斯感到大為震驚,他小小的腦袋認為油缸用去一半汽油便剩下一半,再用去一半又會剩下一半,餘此類推,汽車不可能因為沒有汽油而拋錨。西蒙斯對彭博記者講述這個「小」故事時也忍不住笑稱以一個乳臭未乾的小子來說思想未免太複雜了。

科學數理天賦過人

科學數理天賦過人的西蒙斯1958年於名校麻省理工(MIT)畢業時剛好20歲,1965年在另一名校加州柏克萊學院考獲數學博士,曾回去母校MIT以及哈佛和紐約州立大學(New York State University)石溪分校(Stony Brook University)執教鞭,其後任職美國國家安全局(National Security Agency)的國防分析組(Institute for Defense Analyses,IDA)負責破譯密碼(code cracker),當時越戰方殷,西蒙斯對上司的上司Maxwell Taylor將軍在《紐約時報雜誌》(New York Times Magazine)誇稱美國會輕易打勝仗不以為然,他於是投稿反駁Taylor,認為最理智的做法是徹底從越南撤軍,但卻因此被革職,西蒙斯當時29歲,已婚並有三個子女。1968年,西蒙斯得到石溪大學校長慧眼賞識委任他建立數學部,他立即為數學部引進康乃爾大學數學教授James Ax。

西蒙斯在數學上最突出成就為1974年與數學家陳省身共同研究發明的「陳-西蒙斯理論」(Chern-Simons theory)、證實愛因斯坦相對論描述的扭曲空間的確存在的高深數學理論,而利用陳-西蒙斯恒值(Chern-Simons invariants)更可以解釋物理範疇的宇宙弦理論(string theory);1976年,西蒙斯獲美國數學會(American Mathematical Society)頒授Oswald Veblen幾何學獎。

放棄基本因素分析

西蒙斯初顯投資身手之作是任職石溪大學期間與人合資買入期糖合約,期糖在1974年7個月漲升逾倍,為西蒙斯取得10倍投資回報。1977年,西蒙斯離開石溪創業,他的Monemetrics(Renaissance Technologies前身)聘任IDA舊同事Leonard Baum專責外滙交易。Baum是基本因素派,他根據財經新聞分析滙市趨向,從來不用模型程式買賣,而Baum在1970年代末至1980年代初亦成功為公司賺大錢。西蒙斯分析,在單邊市的情況,利用基本因素的確比模型程式更容易操作,例如強勢政府戴卓爾夫人明言支持英鎊,只要跟風買入便必賺無疑。

然而,今年1月西蒙斯應邀回到MIT發表演說時指出,基本因素分析的弊病是贏錢的時候你會感到自己是天才,但輸錢的日子會認為自己有如白癡,抓破頭皮也想不明白為何大市走勢與自己的分析背道而馳,而模型程式買賣則不會令人產生心理困擾。西蒙斯決定為公司引入模型程式買賣,並先後羅致James Ax、Elwyn Berlekamp等數學專才編寫適合包括股票及商品期貨的計量金融模型,初期還基本因素及模型程式雙線運行,經過幾年實驗比較發現後者的表現優勝得多,1988年3月成立的Medallion基金已是純模型程式運作。

跑贏畢非德索羅斯

而Medallion基金的計量金融模型亦證實經得起時間及市場的考驗,基金成立至2009年,除了1989年虧損4.1%,其餘20年每年最少錄得20%以上的回報【表1】。難能可貴的是,聯儲局1994年一連六次加息,聯邦基金利率由3%升至5.5%,債券及股票投資者都「冇啖好食」,Medallion回報卻高達70.7%;1998年同樣擅於運用計量金融模型的LTCM投資失手並陷入財政危機,Medallion的回報為41.5%;科網股泡沫爆破前的2000年,索羅斯的量子基金幾乎不敢入市,Julian Robertson更於3月關閉他的老虎基金,Medallion卻取得98.5%的投資回報,而標普500指數則下跌10.1%;2007年7月1日,西蒙斯眼見次按及相關市場搖搖欲墜而決定止賺離場,Medallion當年的回報為73%。對沖基金盟主尊稱當之無愧。

財經網站Insider Monkey分析,Medallion的alpha比年輕時的股神畢非德有過之而無不及,假若西蒙斯早出世20年,相信畢非德要將全球首富榮銜讓予西蒙斯(蓋茨的微軟尚未壯大至現今規模;《福布斯》2010年9月統計,西蒙斯以87億美元資產名列全球第80位富豪)。

Medallion從事短線買賣,經常改變投資組合比例或「換馬」,有時甚至參與高頻交易,2005年8月,西蒙斯成立Renaissance Institutional Equities Fund(RIEF)專門投資美國股票,投資策略轉為較長時間持股,翌年12月,西蒙斯為RIEF設限,每月流入新資金不超過15億美元;2007年10月,西蒙斯成立一個專注投資商品期貨基金,名為Renaissance Institutional Futures Fund(RIFF),而RIFF「誕生滿月」即錄得5.2%增長。

基金收費高人一等

對沖基金一直被批評收費昂貴,Medallion的收費更高得嚇人:每年基本管理費已需5%(業界標準收費2%),投資表現獎金則由2000年之前與同業看齊的20%,逐級上升至36%然後44%。市場估計西蒙斯持有Renaissance Technologies約25至50%股權,他同時是Medallion最大持份者,彭博以西蒙斯投資20億美元於Medallion推算(所有數字無法證實,因為西蒙斯一概不予置評),2007年頭三個季度西蒙斯單單從Medallion已賺到10.1億美元投資表現獎金。

2009年10月,西蒙斯宣布將於2010年1月1日正式退休,但保留在Renaissance Technologies非執行主席職位。他今年1月在MIT答覆提問基金成功的秘密時透露,Renaissance Technologies的管理團隊約300位頂級人才,其中約三分之一擁有數學、電腦、天文學等各種科學博士銜頭,在公開而和諧的氛圍下鑽研最適合個別資本市場的金融模型程式,以及因應市況變化修正現有模型。他強調必須知人善用,又表示與聰明的人共事已是一種樂趣。另外,遇到困難不要氣餒,要有永不言放棄的毅力,再加上一點運氣,成功指日可待。

不過,西蒙斯對Renaissance Technologies金融模型程式的結構始終守口如瓶,並明言絕對不會公開模型如何發出買賣訊號。雖然Renaissance Technologies定期公開其投資組合變化【表2】,但相信基金同業專家也難以從中找到玄機,西蒙斯不敗之謎可能成為永遠的秘密。

2011年7月13日 星期三

高頻交易不足為患


阿拉斯加州舉行的「最快手電腦怪傑比賽」(Fastest Geek Competition),讓一眾精通電腦的兒童有機會一展電腦組裝的身手,沐浴於榮耀讚美之中。高頻交易(High frequency trading)其實也一樣,只是注碼高很多而已。

具系統性故障兩大條件

高頻交易商的目的,實質上就是盡量提升其電腦的速度,以便能比其他人搶先一步,窺見股票的買賣雙方叫價;同時又提升電腦的功能,以便利用買賣叫價資訊進行交易圖利。

所謂近水樓台先得月,高頻交易一大競爭優勢在於位置。交易商會盡量把伺服器安置於處理其交易的交易所伺服器附近,總之,兩者之間的接駁線愈短,交易速度就愈快,利潤也會愈可觀。

高頻交易搶去了速度較慢的交易商的利潤,同時為結算中心製造麻煩。不過,高頻交易日益普及──其佔美國股市總成交額或多達四分三,在歐洲的比例則為三分一左右──會否構成系統性風險?

對高頻交易有所顧忌的論者以去年的「閃電股災」(flash crash)為例,說明不受制約的電腦程式橫行無忌,可以造成重大破壞。在閃電股災當天,美股市值在短短三十分鐘內蒸發約1萬億美元。

英倫銀行負責金融穩定事務的執行總監霍爾丹(Andrew Haldane)上周表示,高頻交易令股市「愈來愈複雜及聯繫緊密」,兩者正是導致系統性故障的兩大肇因。

這種想法似乎過慮了。儘管超高速電腦執行的自動演算,令閃電股災挫得更急及更重,但卻沒有造成永久的損害。所有問題交易都取消了,涉及的資金也在二十四小時內歸還原主。所有稱職的交易商(無論是高頻還是普通交易商)如今都調整好自家交易程式,以避免事件重演。

高頻交易也許時不時會擾亂股價,引入停板措施(circuit breakers)等條例應有助減少有關影響。然而,十之八九不可靠的市場謠言也會產生相同效果,但發生的次數卻遠較高頻交易頻仍。

影響不及市場謠言

隨着高頻交易商利用買賣價差賺錢──他們令兩者的距離在過去十年間收窄超過四分三──除了「即日鮮」炒家外,沒有多少人會感到焦慮不安。高頻交易商對金融體系沒什麼貢獻,但也沒造成什麼損害。

譯自THE LEX COLUMN

2011年6月28日 星期二

Too much of a good thing The risks created by complicating a simple idea

Exchange-traded funds


ANY industry would be proud of an average annual growth rate of 34% over ten years and of a global reach from Austria to Taiwan. But the headlong expansion of exchange-traded funds (ETFs), which by May this year controlled almost $1.5 trillion of assets (not far short of the $2 trillion in hedge funds), has become a matter for concern among financial regulators. Could ETFs be the next source of financial scandal, or even of systemic risk?

ETFs have been around since 1990, when the first fund was launched in Canada. The original idea was to create portfolios of shares replicating a stockmarket index, such as the S&P 500. Index-tracking funds had been available to institutional investors since the 1970s. Companies such as Vanguard offered them to individuals in the form of mutual funds. However, as the name suggests, the key feature of an ETF was that it was itself listed on a stockmarket, so that investors could buy and sell it easily. Unlike units in a conventional mutual fund, ETFs can be traded all day long.

Most people still regard these plain-vanilla ETFs as a benign invention that allows small investors to own a diversified portfolio at a low cost. State Street’s $88 billion SPDR fund, which mimics the S&P 500, has a total expense ratio of just 0.09%.

But fund managers quickly elaborated on the basic design. The number of ETFs has swelled to 2,747 (see chart 1). Within equities, there are ETFs based on small-cap companies, value shares, individual industries and every conceivable combination of countries and regions. In bonds, there are ETFs linked to government, corporate and high-yield debt and paper of varying maturities. Some ETFs are based on commodity indices and property markets, others are designed to appeal to the environmentally conscious or to devout Muslims. There are leveraged ETFs which offer a geared return on a given index, inverse ETFs which aim to go down when a benchmark goes up (and vice versa) and, inevitably, leveraged inverse ETFs.

For some, this is a worrying trend, with echoes of the subprime housing crisis, in which financial innovation went out of control. That crisis, too, had its origins in invention with a benign aim: the packaging of mortgages for use as securities for bonds was intended to reduce borrowing costs and disperse risk. Eventually, however, that simple idea transmuted into complex collateralised debt obligations and lower lending standards.

Exotic traded funds

Similarly, the new types of ETF no longer offer the cheapness and diversification of the early varieties. Instead they have become a means for hedge funds to speculate on the market throughout the trading day, allowing them to make complex bets on illiquid asset classes. And the portfolios of some ETFs consist not of a broad range of stocks but of a derivative position with an investment bank as a counterparty.

Official concern is growing. In April three international bodies set out their worries. The Financial Stability Board (FSB), a committee of financial supervisors, issued a report on ETFs. The IMF devoted part of its global financial-stability report to them. And the Bank for International Settlements (BIS) published a paper entitled “Market Structures and Systemic Risks of Exchange-Traded Funds”.

One risk is a lack of liquidity. On May 6th 2010 trading in the American stockmarket seemed to go haywire: the Dow Jones Industrial Average fell by almost 1,000 points in the session and some stocks lost almost all their value. This “flash crash” prompted the authorities to cancel a bunch of trades made at unusual prices. Between 60% and 70% of those trades were in ETFs, far above their actual weighting in the market.

Some investors use ETFs as a quick way of expressing their overall view on the market, while high-frequency traders use the funds as part of their complex arbitrage strategies. But such strategies work only as long as there is someone willing to take the other side of the trade. In chaotic conditions, there may be sellers but no buyers. As the IMF points out,While most ETFs are supported by one or two marketmakers, there is no guarantee of active trading under illiquid conditions.

A linked problem is the tendency for ETFs to be the main way in which investors seek exposure to some asset classes, notably gold. Once upon a time gold bulls had to pay a hefty markup to buy coins or had to purchase shares in gold-mining companies and hope that the management was competent. But gold ETFs have been hugely popular, seeing inflows of $12 billion in 2009 and $9 billion in 2010. The largest gold ETF holds more bullion than all the world’s central banks except those of America, France, Germany and Italy. The IMF also has more. The surge of interest in gold ETFs has been encouraged by (and may have in turn contributed to) a rise in the bullion price. If investors lose faith, the market may become disorderly as they scramble to take their profits.

Some ETF managers also top up their income with fees for lending the securities in their portfolios. There is a risk that, in a period of market disruption when ETF investors want their money back, managers would be forced to recall such loans, adding to liquidity pressures.

Another problem lies in the existence of leveraged ETFs, where losses as well as profits can be magnified. Were a leveraged ETF to suffer huge losses, the reputation of the entire industry might be affected, particularly among private investors. Inverse ETFs offer a way for investors to bet on a fall in an asset class but they may not always deliver such a return over an extended period. “It isn’t hard to give examples in which investors would lose money on a leveraged long ETF if the market went up over a period of significant volatility, or in which they lost money owning a short ETF and the market went down over a period in which there were some sharp rallies,” says Terry Smith, chief executive of Tullett Prebon, a money broker.

Perhaps the biggest concern, and the one with the clearest echoes of the subprime crisis, surrounds “synthetic” ETFs and linked products known as exchange-traded notes (ETNs) and exchange-traded vehicles (ETVs). An ETN is a debt security issued by an index provider or a bank and traded on the market; an ETV is similar, but the debt issuer is a special-purpose vehicle. Collectively these offshoots are known as exchange-traded products (ETPs).

The rationale for concocting this alphabet soup is the desire to create funds linked to illiquid asset classes. It may be too costly or impractical to replicate the targeted index completely. To synthesise it, the ETF provider usually enters into a transaction known as a total return swap with a bank. The bank agrees to pay the provider an amount equal to the return on the chosen benchmark, say an emerging-markets index; the provider hands over cash in return. The bank now has to manage the risk of replicating the index; the provider faces the risk that the bank might go bust. So the ETF provider requires the bank to provide collateral (see diagram).

The financial laboratory revisited

Here’s the rub. The collateral is usually unconnected with the index. The BIS cites the example of an emerging-markets ETF offered by a firm called db x-trackers. The collateral was in the form of equities and bonds. Most of it had nothing to do with emerging markets. Around half of the equity portion was in Japanese shares; another 30% consisted of American and German ones. Of the bonds, three-quarters were American, many of them unrated. Were the bank counterparty to fail, the index provider would be left with assets that were unrelated to the target portfolio.

Worse, the BIS points to a potential conflict of interest when the fund provider is owned by an investment bank. When a bank acts as a marketmaker, it needs to keep an inventory of bonds and stocks so that it can deal with clients’ demands to buy and sell. These positions have to be funded, which can be costly, especially if the securities are illiquid. “By transferring these stocks and bonds as collateral assets to the ETF provider sponsored by the parent bank, the investment banking activities may benefit from reduced warehousing costs for these assets,” the BIS warns.

That raises the danger that an ETF could act as a dumping ground for the unwanted securities on an investment bank’s books. “The synthetic ETF creation process may be driven by the possibility for the bank to raise funding against an illiquid portfolio that cannot otherwise be financed,” says the FSB report. Again, there are parallels with the subprime crisis, where mortgage-backed securities were warehoused in off-balance-sheet ventures.

If doubts emerged about the health of the bank involved in the swap, investors might be inclined to sell their holdings in the ETF or the ETN rather than take their chances on the exact value of the collateral. After all, as the crisis of 2008 showed, when banks are collapsing the value of all kinds of assets takes a battering.

The structure of synthetic ETFs is not a secret. Anyone who reads the documentation carefully should be aware of the nature of a fund and the type of collateral. It is also worth noting that in America these concerns apply only to ETNs and ETVs. In products labelled as ETFs, at least 80% of the portfolio must comprise securities matching the fund’s name.

In Europe synthetic funds make up around half of the ETF sector by assets. However, the European Fund and Asset Management Association, a trade body, points out that the vast majority of them trade under the UCITS (Undertakings for Collective Investments in Transferable Securities) rules, which limit some of the risks outlined by the BIS and the FSB. For example, rules on conflicts of interest restrict the choice of counterparties, a fund cannot have an exposure to any one counterparty that comprises more than 10% of its value, and the chosen collateral is subject to liquidity and credit-quality criteria.


Nevertheless, the rapid trading of ETFs is an area of concern, especially when the underlying assets are illiquid. Creating a synthetic ETF does not eliminate this illiquidity risk, but merely transforms it into a bet on the creditworthiness of a bank. One day that bet will go wrong.

Despite some eerie parallels, it is hard to conclude that ETFs yet pose a systemic risk on the same scale as mortgage-backed securities. Leveraged funds have around $40 billion of assets, less than 3% of the industry total, according to BlackRock, a fund-management group that, under its iShares brand, is the biggest provider of ETFs. Synthetic ETFs had more than $140 billion of assets in May. Though ETPs have been growing rapidly (see chart 2), their total value is less than $200 billion, less than one-seventh of that of conventional ETFs. It seems unlikely that banks have the same kind of exposure to collapsing ETFs as they did to the subprime market.

Even some in the industry are nervous about the profusion of new vehicles. A failure might diminish the appeal of ETFs as a whole. “There are products that are not even funds which are being called ETFs,” reports Deborah Fuhr of BlackRock. “The risk of confusion, disappointment and disillusionment among investors would be very negative for the ETF industry.”

That would be a shame. Fund managers’ fees have always eaten into investors returns; ETFs were a splendid way of letting investors keep more of their money. But like a hyperactive child, the finance sector can never leave a good thing be.


2011年6月26日 星期日

陳家強:不會減股票印花稅 質疑高頻交易是否有利香港

交易科技發展改變市場生態已是不爭的事實,機構投資者、對沖基金不再靠眼光賺錢,而是靠科技。在歐美大行其道的高頻交易(HFT),受制於股票印花稅,在港幾乎無用武之地。不過,財經事務及庫務局局長陳家強卻質疑高頻交易對市場是否有利,強調無意降低印花稅。

「不少學者贊成高頻交易,但從監管者的角度來說,我認為程式交易(Algorithm Trading)非壞事,但懷疑高頻交易的作用,其所帶來的流動性(liquidity),是否香港希望吸引的?又是否值得我們特別鼓勵?」本身是財務學教授的陳家強接受訪問時說。

高頻交易屬於程式交易的一種,特別深得對沖基金的歡心,他們把大手交易「斬件」,利用比眨眼還要少的時間逐一完成,由於每宗交易的差價都很少,故累計的利潤相當可觀。因此,交易費用愈低,對高頻交易投資者愈有利。

陳家強續指出,香港要徵收印花稅,成為高頻交易的天然障礙。「印花稅是重要的收入來源,也有穩定市場的作用,我們不會降低這個稅率。」

印花稅有穩定市場作用

剛過去的財政年度,來自印花稅的收入達510億元,是第二大稅項收入,當中股票印花稅佔49%。

至今在歐美市場使用高頻交易的比例,佔總交投一半,近日新加坡證券交易所(SGX)的數據中心正式開幕,開宗明義是為高頻交易投資者而設,目的是刺激流動性。

香港是否要反其道而行?陳家強不認為香港的做法是「趕客」,相信投資者不只考慮交易成本,還會衡量市場結構。他舉例說,不願見到不受管制的「黑池」,但又不想「趕客」,意味解決方面是把「黑池」納入監管機構的雷達。

「作為國際金融中心,市場的微結構非常重要,例如港交所(388)提議的延長交易時間、收市後競價時段、收窄買賣差價、隱名交易等,都是香港市場結構需要配備的。」陳家強強調,發展方向正確,惟細節需要由港交所制訂。被問及上述建議的反對聲音不少,他表示,要兼顧市場發展和不同人士的意見。

另外,陳家強本月中出訪俄羅斯,而吸引企業來港上市是其中一項任務。他指出,當地政府計劃減持國營企業的權益,香港當然會鼓勵這些國企來港,但單是在海外掛牌,似乎不大可能,因此,鼓勵在香港和俄羅斯兩地上市,是較可行的做法。

由於俄羅斯兩大交易所RTS和Micex即將合併,期望增加成交量,市場相信,當地政府會更加積極邀請俄羅斯國企上市,令香港較難攔途截劫。