聯儲局主席Janet Yellen昨晚在紐約Economic Club的演講，為市場打下一支強心針，在這番被市場認為相當Dovish的講話下，多個股票市場都顯著上升。
但其實Yellen講了甚麼？
其實各位是可以在聯儲局的網站觀看Yellen演講的全文，以下就是從中選取的一些演講內容，值得各位留意。
較多傳媒轉載的一段，就是Yellen在演講開首重申FOMC認為「未來只會慢慢調高Federal Fund Rate」
…the Committee stated in December, and reiterated at the two subsequent meetings, that it “expects that economic conditions will evolve in a manner that will warrant only gradual increases in the federal funds rate…
在這一段之後，Yellen 指這個「慢慢加息」的路綫預測，是建基於FOMC預這有助未來實體經濟活動及通脹走向達標，但她重申FOMC這個利率走向的預測不是一個承諾，這利率預測是可以隨經濟實況而改變的。
Importantly, this forecast is not a plan set in stone that will be carried out regardless of economic developments. Instead, monetary policy will, as always, respond to the economy’s twists and turns so as to promote, as best as we can in an uncertain economic environment, the employment and inflation goals assigned to us by the Congress.
在演講中，Yellen指出整體就業增長相當理想。
On balance, overall employment has continued to grow at a solid pace so far this year, in part because domestic household spending has been sufficiently strong to offset the drag coming from abroad.
但她擔心其他地區的經濟增長疲弱，可能拖累美國經濟。
In particular, foreign economic growth now seems likely to be weaker this year than previously expected, and earnings expectations have declined. By themselves, these developments would tend to restrain U.S. economic activity.
到底甚麼國外因素會影響到美國經濟? Yellen 在演講較後段就指出，中國經濟放緩及油價未來走向，都是特別令人擔心的。
One concern pertains to the pace of global growth, which is importantly influenced by developments in China. There is a consensus that China’s economy will slow in the coming years as it transitions away from investment toward consumption and from exports toward domestic sources of growth. There is much uncertainty, however, about how smoothly this transition will proceed and about the policy framework in place to manage any financial disruptions that might accompany it. These uncertainties were heightened by market confusion earlier this year over China’s exchange rate policy.
Yellen特別提到，中國經濟轉型可能為金融體系帶來壓力，為市場帶來不確定性。
A second concern relates to the prospects for commodity prices, particularly oil. For the United States, low oil prices, on net, likely will boost spending and economic activity over the next few years because we are still a major oil importer. But the apparent negative reaction of financial markets to recent declines in oil prices may in part reflect market concern that the price of oil was nearing a financial tipping point for some countries and energy firms. In the case of countries reliant on oil exports, the result might be a sharp cutback in government spending; for energy-related firms, it could entail significant financial strains and increased layoffs. In the event oil prices were to fall again, either development could have adverse spillover effects to the rest of the global economy.
油價方面，低油價可能為個別油企甚至國家帶來財務壓力，前者可能大規模裁員，後者則會大削財政開支，這些都會對環球經濟帶來打擊。
其中一個可能影響美國經濟的渠道，就是上述情況問題令金融市場融資能力轉趨張，拖慢美國濟增長。
If such downside risks to the outlook were to materialize, they would likely slow U.S. economic activity, at least to some extent, both directly and through financial market channels as investors respond by demanding higher returns to hold risky assets, causing financial conditions to tighten.
Yellen又提到，她認為長期而言間限美國經濟增長的阻力，包括上述的國外因素、美元匯價上升、建屋活動疲弱及生產力增長持續偏低等，將會消失，這將有助美國的「自然利率」回升，令聯儲局有加息的空間。
Looking beyond the near term, I anticipate that growth will also be supported by a lessening of some of the headwinds that continue to restrain the U.S. economy, which include weak foreign activity, dollar appreciation, a pace of household formation that has not kept up with population and income growth and so has depressed homebuilding, and productivity growth that has been running at a slow pace by historical standards since the end of the recession. If these headwinds gradually fade as I expect, the neutral federal funds rate will also rise, in which case it will, all else equal, be appropriate to gradually increase the federal funds rate more or less in tandem to achieve our dual objectives.
Yellen明言，上述「阻力將會消失」的假設，正是FOMC認為可以慢慢加息的基礎。
Implicitly, this expectation of fading headwinds and a rising neutral rate is a key reason for the FOMC’s assessment that gradual increases in the federal funds rate over time will likely be appropriate.
但她又補充一句，無人可以知道阻力何時消散，所以加息路綫仍有改變的空間。
…no one can be certain about the pace at which economic headwinds will fade. More generally, the economy will inevitably be buffeted by shocks that cannot be foreseen. What is certain, however, is that the Committee will respond to changes in the outlook as needed to achieve its dual mandate.
通脹方面，Yellen承認近期通脹數據較其預計的更高，但她重申目前仍未能確定通脹加速是否會持續的趨勢。
…core PCE inflation, which strips out volatile food and energy components, was up 1.7 percent in February on a 12 month basis, somewhat more than my expectation in December. But it is too early to tell if this recent faster pace will prove durable. Even when measured on a 12-month basis, core inflation can vary substantially from quarter to quarter and earlier dollar appreciation is still expected to weigh on consumer prices in the coming months. For these reasons, I continue to expect that overall PCE inflation for 2016 as a whole will come in well below 2 percent but will then move back to 2 percent over the course of 2017 and 2018, assuming no further swings in energy prices or the dollar.
Yellen在演講後段又指，雖然有指標顯示通脹預期有下跌的情況，例如市場通脹預期就在過去一年半持續下跌。
there have been signs that inflation expectations may have drifted down. Market-based measures of longer-run inflation compensation have fallen markedly over the past year and half, although they have recently moved up modestly from their all-time lows.
但Yellen引述聯儲局內部的分析指，市場價格推算的通脹預期下跌，只因為通脹風險溢價及流動性因素，令市場要求的通脹補償（Inflation Compensation）減少。
Analysis carried out at the Fed and elsewhere suggests that the decline in market-based measures of inflation compensation has largely been driven by movements in inflation risk premiums and liquidity concerns rather than by shifts in inflation expectations…
…Moreover, measures of longer-run expected inflation gleaned from surveys of business and financial economists, such as those reported in the Survey of Professional Forecasters, the Blue Chip survey, and the Survey of Primary Dealers, have largely moved sideways in the past year or two. Taken together, these results suggest that my baseline assumption of stable expectations is still justified.
Yellen在總結部份特別提及目前低息環境下，聯儲局以利率處理高通脹的能力，高於處理經濟及通脹放緩的能力
If economic conditions were to strengthen considerably more than currently expected, the FOMC could readily raise its target range for the federal funds rate to stabilize the economy. By contrast, if the expansion was to falter or if inflation was to remain stubbornly low, the FOMC would be able to provide only a modest degree of additional stimulus by cutting the federal funds rate back to near zero
但她重申，利率政策以外，聯儲局仍有足夠工具去調控長期利率及支持經濟，例如Forward Guidance。（有傳媒就特別留意到，Yellen無直接提及負利率政策的可能性。）
Even if the federal funds rate were to return to near zero, the FOMC would still have considerable scope to provide additional accommodation. In particular, we could use the approaches that we and other central banks successfully employed in the wake of the financial crisis to put additional downward pressure on long-term interest rates and so support the economy–specifically, forward guidance about the future path of the federal funds rate and increases in the size or duration of our holdings of long-term securities
而她又認為，市場對利率走向的預期，某程度為市場提供「自動調節」的勁能，例如在年初的動盪市況，市場自動預計未來加息步伐放緩，壓低長期利率，舒解金融市場的緊張狀況。
Financial market participants appear to recognize the FOMC’s data-dependent approach because incoming data surprises typically induce changes in market expectations about the likely future path of policy, resulting in movements in bond yields that act to buffer the economy from shocks. This mechanism serves as an important “automatic stabilizer” for the economy. As I have already noted, the decline in market expectations since December for the future path of the federal funds rate and accompanying downward pressure on long-term interest rates have helped to offset the contractionary effects of somewhat less favorable financial conditions and slower foreign growth…
… Such a stabilizing effect is one consequence of effective communication by the FOMC about its outlook for the economy and how, based on that outlook, policy is expected to evolve to achieve our economic objectives
