BoG 改進的外匯匯率模型：似曾相識的案例？

距離加納最新國際貨幣基金組織 (IMF) 計劃第三次審查結束還有不到一周時間，當局正忙著表明

Ghana's central bank will begin factoring all forex transactions among banks and between banks and their customers into the rate, a move to address the re-emergence of parallel FX exchange rates in the country.

加納中央銀行將開始將銀行之間以及銀行與其客戶之間的所有外匯交易納入匯率中，此舉是為了解決該國重新出現的平行外匯匯率問題。

The Bank of Ghana (BoG) will factor into the rate all the forex transactions among banks and between banks & their customers (above $10,000) in Ghana. The only “improvement” in this “revamped” model, though, is that the rate will now capture transactions with a cut-off time of 3:30 pm instead of the threshold of 2 pm in the previous model.

加納銀行 (BoG) 將把加納銀行之間以及銀行與其客戶之間的所有外匯交易（超過 10,000 美元）納入費率。不過，這個「改進」模型中唯一的「改進」是，該費率現在將捕獲截止時間為下午 3:30 的交易，而不是先前模型中的閾值下午 2 點。

But why will the BoG try to present this less-than-revolutionary change as something epic?

但為什麼 BoG 會試圖將這種不那麼革命性的變化呈現為史詩般的東西呢？

The underlying problem is the re-emergence of Nigeria-style “parallel” FX exchange rates in Ghana. The “weighted median” or average rate published by the BoG daily, which is close to the Bloomberg one, has diverged significantly from what real people trying to buy FX on the open market often get.

根本問題是尼日利亞式的「平行」外匯匯率在加納重新出現。英國央行日報公佈的「加權中位數」或平均匯率與彭博社公佈的匯率接近，但與試圖在公開市場購買外匯的真實人們經常得到的匯率存在顯著差異。

For example, the BoG says the average USD-GHS selling rate for yesterday was ¢15.83. Yet, surveys by market research outlets show that forex bureaus were selling above ¢16.7. If one is lucky enough to get USD from a bank, the rate would have been at nearly ¢16. Fintech and card services providers quote above ¢17.

例如，BoG 表示，昨天美元兌 GHS 的平均賣出價為 15.83 歐元。然而，市場研究機構的調查顯示，外匯局的拋售價格高於 16.7 歐元。如果有幸從銀行獲得美元，匯率將接近 16 英鎊。金融科技和卡片服務提供商的報價高於 17 歐元。

Large FX market premiums of this kind are intensely disliked by the IMF because they suggest underlying inefficiency.

國際貨幣基金組織非常不喜歡外匯市場的這種巨額溢價，因為這表明潛在的低效率。

The whole scheme raises a lot of questions, especially in light of all the muck surrounding the gold refinery the government is asking the BoG to invest in.

整個計畫引發了許多問題，特別是考慮到政府要求央行投資的黃金精煉廠周圍存在大量問題。

Promoting bullion as an investment option to stem dollar demand is a rational decision. The question, however, is scale.

推廣黃金作為抑制美元需求的投資選擇是一個理性的決定。然而，問題在於規模。

A lot of investors have to be convinced. Purely from a technical analysis point of view, gold has one disadvantage compared to the dollar in Ghana's specific case. Contrary to claims by some researchers that gold is a “zero beta” asset, it actually fluctuates against relevant indices by quite a lot. In short, it is risky.

許多投資者必須被說服。純粹從技術分析的角度來看，在加納的具體情況下，與美元相比，黃金有一個劣勢。與一些研究人員聲稱黃金是「零貝塔」資產的說法相反，它實際上相對於相關指數的波動相當大。簡而言之，這是有風險的。

The dollar on the other hand has performed very steadily against the GHS over time. Since 1994, it has always gained value. In May 2023, some lecturers at Tarkwa and Takoradi used ARIMA to forecast USD-GHS rates for 2024 and 2025 at less than ¢12.5. They got it spectacularly wrong.

另一方面，隨著時間的推移，美元兌 GHS 的表現非常穩定。自1994年以來，它一直在增值。 2023 年 5 月，Tarkwa 和 Takoradi 的一些講師使用 ARIMA 預測 2024 年和 2025 年美元兌 GHS 匯率將低於 12.5 美分。他們錯得離譜。

Thus, while it looks like one can almost always count on getting both the price increase return plus the dollar return by buying gold, history actually suggests otherwise.

因此，雖然看起來人們幾乎總是可以指望透過購買黃金來獲得價格上漲回報和美元回報，但歷史實際上表明情況並非如此。

Eg: if one had bought gold in 2012 and sold it in 2015, one would have made a ~72% nominal cedi profit. But buying $ would have yielded ~140%.

例如：如果有人在 2012 年購買黃金並在 2015 年出售黃金，那麼人們將獲得約 72% 的名義塞地利潤。但購買美元的收益率約為 140%。

There is also the issue of BoG simply displacing gold that it could otherwise have sold for USD in the international markets to cater to local investors.

還有一個問題是，央行只是簡單地取代黃金，否則它本來可以在國際市場上以美元出售黃金，以滿足當地投資者的需求。

In some sense, therefore, the actual USD in circulation doesn't really change as the BoG has to forgo the benefits of increasing its own USD reserves and focus instead on serving local investors' appetite for a hedge against the Cedi's notorious depreciation streak.

因此，從某種意義上說，實際流通中的美元並沒有真正改變，因為央行必須放棄增加自身美元儲備的好處，轉而專注於滿足當地投資者對沖塞地臭名昭著的貶值趨勢的興趣。

If the gold coin model does scale, it is likely to cannibalise the treasury bill market more than dollar demand given the BoG's superior credit compared to the Govt of Ghana. It bears reminding readers that in the latest treasury bill auction, the undersubscription rate was more than 40%. It would be interesting to see how the govt would react if the gold coins thing caught on.

如果金幣模式確實擴大規模，鑑於央行的信用優於加納政府，它對國庫券市場的蠶食可能會超過美元需求。值得提醒讀者的是，在最新的國債拍賣中，認購不足率超過40%。如果金幣事件流行起來，看看政府會如何反應，這將是很有趣的。