近日聯匯觸及弱方兌換保證，資金開始流走，被喻為「聯匯之父」的景順投資管理集團首席經濟師祈連活，以〈恪守原則vs按酌情權管理聯匯〉（Rules versus Discretion in Managing the HK$ Peg）為題，給本報撰文，就2015年美國開始加息惟港息濟後、聯匯套戥機制是否過慢要加入酌情權等問題，分享其見解。
北水湧入令港元長期偏強
祈連活亦擔任外匯基金諮詢委員會轄下貨幣發行委員會委員。
「香港貨幣發行局制度的最貼切形容，是匯率在介乎每美元兌7.75至7.85港元之間波幅區內運作。
外界所謂金管局入市干預，其實並不是該局主導，反而是商業銀行引發，原因是該局設立了雙邊兌換保證，確保在7.75價位接美元沽港元，及在7.85價位接港元沽美元。就像最近當港元匯率轉弱，觸及兌換價7.85或更低水平時（如7.86），銀行便選擇向該局以7.85港元買入1美元，因為較在市場用7.86買入更便宜。
同一原理發生在匯率偏強時。換句話說，不是金管局介入市場『托高』匯率或作出捍衞，該局只是履行兌換保證承諾的責任。
2015年底聯儲局展開加息以來，港元拆息落後美元拆息，因港匯一直處於遠較弱方兌換保證價偏強位置。
當中有兩個問題出現，第一為何港元長時間偏強？答案是過去一段時間內地資金透過滬港通、深港通等機制，南向流入帶來更多資金，內地投資者亦熱衷購買本港房地產，他們喜投資可作避風港的資產，對港美息差分別則不太敏感。
金管局目標是匯率非利率
無論如何，弱方兌換保證在4月12日啟動，金管局已承接銀行513億港元沽盤，令結餘收細港息開始上升。但要處理2008年流入本港逾1.3萬億元資金，仍有漫長道路。隨之而來的第二個問題，是為何金管局不加快入市行動，提早買港元沽美元？
無疑金管局是有權可以這樣做，就如當新股招股資金緊張時，該局可提供流動性然後再收回資金。不過藉干預調節利率，絕對不是恪守貨幣發行局制度原則下的一項酌情權，若然，市場參與者便會認為，金管局政策目標是利率而不是匯率，而且該局亦可能招致失敗，當資金流入時該局要不斷買入港元，利率可能持續低企，房地產依然強勁。
其實，過去亦曾發生過（2006至2008年間）港美息差擘闊超過1.5厘現象，所以最近港美息差拉闊至1厘或以下，並非歷史高位。
簡單而言，在原則主導的匯率機制下進行酌情干預，可能導致金管局失去市場信賴，所以我認為，最佳做法是該局維持現有制度的可信性，在7.75至7.85匯率波幅之間恪守原則，保持高透明度操作。」
祈連活文章英文原文：
Rules versus Discretion in Managing the HK$ Peg
The Hong Kong currency system is often referred to as a Linked Exchange Rate System (LERS) centred on HK$7.80 per US$1.00. However, in reality the HKMA is better described as operating an exchange rate band with the exchange rate varying between 7.75 and 7.85 per US$1.00.
It is true that in order to issue banknotes the three note-issuing banks must pay US$ at the central 7.80 rate to the HKMA in order to obtain Certificates of Indebtedness (CIs) which in turn authorize the banks to issue HK$ banknotes. However, banknotes today only comprise about 6% of total HK$M3 (the broad money supply held by households and companies in Hong Kong). By contrast, the vast majority of foreign exchange transactions occur in the open market at exchange rates somewhere between the two limits of 7.75 and 7.85 – i.e. within the convertibility band.
A key point to note about the system is that so-called interventions by the HKMA are in fact not initiated by the HKMA at all, but rather by the commercial banks. The reason is that the HKMA has issued “Convertibility Undertakings” (CU) or promises to sell Hong Kong dollars at 7.75, and US dollars at 7.85 in whatever amounts the market requires.
So whenever the HKD/USD exchange rate reached or exceeded the strong side CU – say, 7.74 – it became cheaper for banks to buy HK dollars from the HKMA, obtaining HK$7.75 for every US$ 1.00, than to buy in the market where they would obtain only HK$7.74 for every US$ 1.00.
Conversely, as recently, when the exchange rate reached the weak side CU -- say, 7.86 – it became cheaper for the banks to buy US dollars from the HKMA at 7.85 than to buy from the market at 7.86.
In other words, the banks typically approach the HKMA to do the transactions. It is not the HKMA stepping into the market to “prop up” the currency or defend it. In response to demand from the banks, the HKMA has been simply fulfilling its obligation under the CU to supply US$ at 7.85.
Another key point to be aware of is that since the Global Financial Crisis in 2008, inflows into Hong Kong have been enormous, pushing the exchange rate to the 7.75 strong side CU for much of the time. This resulted in sales of US$ by the banks to the HKMA in exchange for HK$ requested by their customers. In fact the monetary base, or the key part of the HKMA’s balance sheet that includes these transactions, increased from HK$ 348 billion on 30 September 2008 to HK$ 1,663 billion on 26 April 2018, an increase of over HK$1.3 trillion.
Just as the US Federal Reserve is currently reducing the size of its balance sheet – a process that started in October 2017 – the HKMA will also want its balance sheet to diminish in size. But in Hong Kong the only way this can happen naturally through market forces is if the exchange rate falls to the weak side CU level of 7.85, resulting in outflows of HK$ or sales of HK$ by the banks to the HKMA at 7.85 and the debiting of banks’ settlement accounts at the HKMA. This process would also tighten up the Hong Kong money market, pushing interest rates upwards.
However, since December 2015 when the Fed started raising interest rates, HIBOR rates have generally lagged behind LIBOR rates, precisely because the exchange rate remained well above the weak side CU, and there was no draining of funds out of the HK$ money markets.
This raises two questions. First, why did the HK$ remain so much stronger than 7.85 for so long? And second, why did the HKMA not push the process forward (and close the HIBOR-LIBOR gap by stepping into the market to sell US$ (or buy HK$) before the exchange rate reached 7.85?
The answer to the first question is that inflows from the Mainland have created more liquidity in Hong Kong than in the past. The Hong Kong-Shanghai Connect and the Hong Kong-Shenzhen Connect schemes have seen a predominance of southbound flows. In addition, strong buying interest in the Hong Kong property market by Mainland investors has also been an additional source of HKS$ liquidity.
Because these Mainland investors are possibly not so concerned with the interest rates or short term returns they receive in Hong Kong, but are more concerned about keeping assets in Hong Kong as a kind of long term, safe haven investment, they are perhaps less sensitive to the interest rate differentials between the HK$ and US$ money markets.
The result is that it has taken time for the HIBOR rates to follow LIBOR. (An additional factor to mention is that since the end of 2017 US$ LIBOR has increased relative to either EURIBOR or the Sterling LIBOR, exacerbating the apparent difference between HIBOR and LIBOR.)
Nevertheless, for the first time since the 7.85 CU level was set up in 2005, the weak side CU was at last triggered by sales of HK$ to the HKMA on 12th April 2018. Since then there have been numerous such episodes, resulting in cumulative sales of US$ 6.5 billion against purchases of HK$ 51.3 billion from the banks (up to April 18). This reduction in the amount of HK$ in the banks’ settlement accounts is now gradually raising HK$ interest rates (including HIBOR) in exactly the way intended.
Clearly there is still a long way to go in terms of reducing the HK$1.3 trillion expansion of Hong Kong’s monetary base since 2008. So this brings us to the second question: why doesn’t the HKMA accelerate the process by intervening within the convertibility band to sell US$ or buy HK$?
The HKMA unquestionably has the powers to do this. After all, from time to time it provides liquidity and then withdraws it – for example in the case of IPOs.
However, intervention to adjust interest rates would definitely be a discretionary action that is not in accordance with the “rules” of the currency board mechanism. Market participants will soon start to think that the HKMA is targeting interest rates rather than the exchange rate band. In any case, given the motivation of the Mainland investors in Hong Kong (i.e. not based on short term interest rate differentials), such intervention might not succeed. The HKMA could then be buying HKD but inflows could continue, keeping rates low and the property market strong.
Moreover, in the past (2006-08), the HIBOR-LIBOR gap at times exceeded 150 basis points (1.5%), so the current gap of less than 100 basis points (1%) is not unusually large by historical standards.
Discretionary intervention implies that the HKMA it engages in a never-ending game of trying to outguess the market. This could easily result in a loss of long term credibility. In my view it is better that the HKMA preserve and enhance the HKMA’s credibility by observing the “rules” of the currency board system. The best way to do that is to operate the 7.75-7.85 band mechanism based on transparent rules that everyone can understand, not based on discretion.