貨幣價格上漲，不僅是因為美國聯儲局 (1/2)

Recently Yahoo News on-line reported the following:

The Price of Money Is Going Up, and It’s Not Only Because of the Fed (1/2)

Jamie Rush, Martin Ademmer, Maeva Cousin and Tom Orlik

Mon, November 6, 2023 at 8:00 a.m. GMT+8

(Bloomberg) -- What’s the most important price in the global economy? The price of oil? The price of semiconductors? The price of a Big Mac? More important than any of these is the price of money. For more than three decades it was falling. Now it’s going up. Ask most people how the price of money is set, and they’ll say central banks. True, when it comes to direct control of US interest rates, the Federal Reserve calls the shots. But there’s a deeper logic at work. Fundamentally, the price of money—like the price of anything else—reflects the balance of supply and demand. Higher supply of saving pushes rates down. More investment demand pushes them up.

For the economics wonks, the price of money that balances saving and investment while keeping inflation stable has another name: the “natural rate of interest.” To see why this concept is central to policymaking, imagine what would happen if the Fed set borrowing costs well below the natural rate. With money too cheap, there would be too much investment, not enough saving, and the economy would overheat—resulting in spiraling inflation. Flipping that around, if the Fed set borrowing costs above the natural rate, there would be too much saving, not enough investment, and the economy would cool—resulting in rising unemployment.

For more than three decades, borrowing costs in the US were trending down. By our estimates, and adjusting for inflation, the natural rate of interest for 10-year US government bonds fell from a bit more than 5% in 1980 to a little less than 2% over the past decade.

To find out what drove interest rates lower, and to forecast where the natural rate might go in the future, we built a model of the big factors driving the supply of saving and demand for investment. Our dataset spans a half-century and 12 advanced economies deeply enmeshed in the global financial system. The results show that one of the most important reasons for the drop in the natural rate was weaker growth. In the 1960s and ’70s, a swelling workforce and rapid productivity gains meant average annual growth of gross domestic product was close to 4%. Strong growth created a powerful incentive to invest—lifting the price of money.

By the 2000s those drivers were running out of steam. After the global financial crisis of 2007-08, average annual GDP growth slumped to around 2%. A more sluggish economy meant the attractiveness of investing for the future was weaker—dragging the price of money lower.

Shifting demographics contributed in another way. From the 1980s on, as the baby boom generation started squirreling away more money for retirement, the supply of saving went up—adding more downward pressure on the natural rate.

Other factors also contributed. On the saving side of the equation, China’s economy was growing fast, saving a lot and channeling those savings into US government bonds. And in the US, income inequality went up—high earners tuck away a higher share of their income, which further increased the supply of saving.

On the investment side, computers got cheaper and more powerful, meaning companies didn’t have to spend so much upgrading their technology—lowering investment demand and dragging the natural rate lower.

For the US economy, that fall in the price of money had profound consequences. Bargain-basement borrowing costs meant households could take on bigger mortgages. In the early 2000s many bit off more than they could chew. There were lots of reasons behind the subprime mortgage meltdown and global financial crisis; falling borrowing costs were one.

And cheaper money meant that even as US federal debt almost tripled, from 33% of GDP at the turn of the century to nearly 100% today, the cost of servicing that debt remained low, allowing the government to continue spending on education, infrastructure and the military.

For the Federal Reserve, a lower natural rate meant less space to cut rates during recessions, leading to much hand-wringing about the diminished firepower of monetary policy.

(to be continued)

Translation

（彭博）－全球經濟中最重要的價格是什么？ 石油價格？ 半導體的價格？ 巨無霸的價格？ 比這些都更重要的是貨幣的價格。 三十多年來，它一直在下降。 現在它正在上漲。 如果問大多數人貨幣價格是如何設定的，他們會說央行。 誠然，當談到直接控制美國利率時，是由美國聯儲局會發號施令。 但還有更深層的邏輯在運作。 從根本上來說，貨幣的價格 - 就像其他任何東西的價格一樣 - 反映了供求平衡。 更多儲蓄會壓低利率。 更多的投資需求推高對貨幣供應要求。

對經濟學迷來說, 平衡儲蓄和投資同時維持通膨穩定的貨幣價格還有另一個名字：「自然利率」。 要了解為什麼這個概念對於政策制定至關重要，想想如果聯儲局將借貸成本設定為遠低於自然利率，會發生什麼事。 如果貨幣太便宜，投資就會過多，儲蓄就會不足，經濟就會過熱，導致通貨膨脹螺旋上升。 反過來說，如果聯儲局將借貸成本設定為高於自然利率，儲蓄就會過多，投資就會不足，經濟就會降溫，導致失業率上升。

三十多年來，美國的借貸成本呈現下降趨勢。 根據我們的估計，並加入通貨膨脹因數進行調整，10年期美國政府債券的自然利率從1980年的略高於5%下降到過去十年中的略低於2%。

為了找出推動利率下降的原因，並預測未來自然利率的走向，我們建立了一個模型，描述驅動儲蓄供給和投資需求的主要因素。 我們的資料收集跨越了半個世紀，涉及 12 個深深融入全球金融體系的已開發經濟體。 結果顯示，自然利率下降的最重要原因之一是成長疲軟。 在 1960 年代和 1970 年代，勞動力的膨脹和生產率的快速提高意味著國內生產總值的年均增長率接近 4%。 強勁的成長創造了強大的投資意欲 - 推高了貨幣價格。

到了 2000 年代，這些動力已經筋疲力盡。 2007-08年全球金融危機後，年均GDP成長率降至2%左右。 經濟更加低迷意味著未來投資的吸引力減弱，從而拖累貨幣價格走低。

人口結構的變化以另一種方式做出了貢獻。 從 1980 年代開始，隨著嬰兒潮世代開始為退休儲蓄更多的錢，儲蓄供給增加，自然利率面臨更大的下行壓力。

其他因素也有貢獻。 在儲蓄方面，中國經濟成長迅速，儲蓄大量，並將這些儲蓄轉化為美國政府債券。 在美國，收入不平等加劇 - 高收入者將更高比例的收入存起來，這進一步增加了儲蓄供應。

在投資方面，電腦變得更便宜、更強大，這意味著公司不必花費太多資金來升級技術，從而降低投資需求並拉低自然利率。

對美國經濟來說，貨幣價格的下跌產生了深遠的影響。 廉價的借貸成本意味著家庭可以承擔更大的抵押貸款。 2000 年代初，許多人貪得無厭。 次貸危機和全球金融危機背後的原因是多方面的； 借貸成本下降就是其中之一。

更便宜的資金意味著，儘管美國聯邦債務幾乎增加了兩倍，從世紀之交佔GDP 的33% 增加到今天的近100%，但償還債務的成本仍然很低，使政府能夠繼續在教育、基礎設施和軍隊的開支。

對聯儲局來說，較低的自然利率意味著經濟衰退期間降息的空間較小，導致因貨幣政策火力減弱而要絞盡腦汁。

（待續）