享有“債券之王”美譽(yù)的比爾·格羅斯認(rèn)為，股市“目前的定價(jià)太過依賴預(yù)期”，他的理由是，并不確信美國(guó)總統(tǒng)特朗普能推動(dòng)經(jīng)濟(jì)迅速增長(zhǎng)，因?yàn)槊绹?guó)的生產(chǎn)率不如以往。

“高增長(zhǎng)率及其推動(dòng)的生產(chǎn)力可能已成遙遠(yuǎn)的回憶，一去不返。”格羅斯在本周四上午發(fā)布的月度投資展望中如是說。

格羅斯曾因擔(dān)任全球共同基金巨頭太平洋投資管理公司（Pimco）的明星債券投資者蜚聲業(yè)內(nèi)，目前擔(dān)任駿利資產(chǎn)管理集團(tuán)基金經(jīng)理。他時(shí)而睿智時(shí)而諷刺的月度投資展望廣受歡迎。

本月的投資展望開頭提出一個(gè)有點(diǎn)怪異的問題。（格羅斯問：心愛的寵物和一個(gè)不認(rèn)識(shí)的人二選一，必須殺死一個(gè)，你會(huì)怎么選？）

但接下來，他深入剖析現(xiàn)實(shí)世界經(jīng)濟(jì)學(xué)家和決策者當(dāng)前面對(duì)的難題：近年來經(jīng)濟(jì)增長(zhǎng)的一大要素增長(zhǎng)停滯不前，原因成謎。

所謂全要素生產(chǎn)率，實(shí)際上是指勞動(dòng)力和資本轉(zhuǎn)化為產(chǎn)品和服務(wù)的效率。對(duì)發(fā)達(dá)經(jīng)濟(jì)體而言，科技、教育、甚至公共衛(wèi)生領(lǐng)域的進(jìn)展都包含在全要素生產(chǎn)率中，有時(shí)可能體現(xiàn)得并不明顯，但都十分重要。

在關(guān)于生產(chǎn)率的爭(zhēng)論中，美國(guó)西北大學(xué)經(jīng)濟(jì)學(xué)家羅伯特·戈登等悲觀人士認(rèn)定，人們享用電氣化、室內(nèi)暖通、汽車、噴氣式發(fā)動(dòng)機(jī)和互聯(lián)網(wǎng)等巨大科技進(jìn)步“低垂的果實(shí)”后，美國(guó)經(jīng)濟(jì)的黃金歲月可能已經(jīng)遠(yuǎn)去。而樂觀人士認(rèn)為，我們無法預(yù)見未來的科技進(jìn)步，有可能科技發(fā)展還能繼續(xù)推動(dòng)經(jīng)濟(jì)強(qiáng)勁增長(zhǎng)。

本周稍早，美聯(lián)儲(chǔ)主席珍妮特·耶倫在密歇根大學(xué)的演講也提及這個(gè)話題。她當(dāng)時(shí)指出，雖然就業(yè)增長(zhǎng)強(qiáng)勁，但最近生產(chǎn)率“非常令人失望”。

耶倫說：“經(jīng)濟(jì)增長(zhǎng)如此緩慢還能創(chuàng)造如此多就業(yè)，顯示問題非常嚴(yán)重。說明生產(chǎn)效率增長(zhǎng)很慢。”

格羅斯則借助投資展望里的燒腦問題指出，對(duì)經(jīng)濟(jì)學(xué)家來說，“答案不分對(duì)錯(cuò)。”可在他看來，投資者過于依賴根據(jù)歷史表現(xiàn)編制的模型，但用過去預(yù)測(cè)未來并不一定準(zhǔn)確。也正是基于已有估值，股市、高收益?zhèn)荣Y產(chǎn)的價(jià)格普遍太高。

格羅斯寫道：“人們對(duì)未來的希望太美好，所以股市估值過高，對(duì)增長(zhǎng)太樂觀，所以高收益?zhèn)乐狄膊坏停匈Y產(chǎn)價(jià)格都炒高了。只有熱愛估值模型，強(qiáng)烈依靠歷史數(shù)據(jù)做判斷的投資者會(huì)相信，今后還會(huì)出現(xiàn)過去六年、或者雷曼兄弟倒閉之前幾十年里同樣高額的回報(bào)。”（財(cái)富中文網(wǎng)）

譯者：Pessy

審稿：夏林

Bill Gross, the so-called “Bond King,” thinks stocks are currently "priced for too much hope," and here's why: He doubts President Trump can deliver rapid economic growth because the United States simply isn’t as productive as it used to be.

“High rates of growth, and the productivity that drives it, are likely distant memories from a bygone era,” he notes in his monthly investment outlook released Thursday morning.

Gross, who rose to prominence as a star bond investor with Pimco, is now a fund manager with Janus, and his sometimes clever, tongue-in-cheek monthly newsletters have a wide following.

This month the newsletter starts with a rather grotesque brainteaser. (Gross asks: “If forced to choose between killing your favorite pet or an anonymous human being, what would you do?”)

But then he dives into the real-life conundrum currently facing economists and policymakers: An important ingredient of economic growth has stalled in recent years, and it’s still a mystery as to why.

Known as total factor productivity, it’s essentially a measure of how efficient workers and capital are in producing services and products. Improvements in technology, education, and even public health can factor into this somewhat ambiguous, but crucial variable for developed economies.

The pessimists in the debate, like Northwestern University economist Robert Gordon, have argued that the best days for the U.S. economy may be behind us, after we already picked the “l(fā)ow hanging fruit” of massive technological improvements like electrification, indoor plumbing, the automobile, jet engines and the Internet. Optimists, meanwhile, argue we cannot foresee the technological improvements of the future, which may still lead to strong economic growth.

Federal Reserve Chairwoman Janet Yellen touched on the debate earlier this week in a speech at the University of Michigan, noting that recently productivity has been “very disappointing,” despite stronger job growth.

“The fact that you can create that many jobs in the context of growth that is so low points to a significant problem,” she said. “And the problem is that productivity growth is very low.”

As with his brainteasers, Gross notes, “There is no right or wrong answer” for economists. But in his view, investors are relying too heavily on models based on history that may not repeat itself. And for this reason, stocks, high-yield bonds, and other asset prices are too high.

“Equity markets are priced for too much hope, high yield bond markets for too much growth, and all asset prices elevated to artificial levels that only a model driven, historically biased investor would believe could lead to returns resembling the past six years, or the decades predating Lehman,” Gross wrote.