In a statement, the central bank said it was cutting rates to a target range of 0% to 0.25%.

The Fed included dramatic moves to keep credit flowing to businesses and families, encouraging banks to tap trillions of dollars in equity and liquid assets built up as capital buffers since the global financial crisis to support people whose lives may be upended by the virus.

S&P 500 e-minis fell about 5% to their limit down. Nasdaq 100 e-minis were down 4.5%. Dow e-minis were down 4.53%. The U.S. dollar fell against the euro and Japanese yen in response.

SEAN CALLOW, FX ANALYST, WESTPAC, SYDNEY:

"It's important not to be too broad about 'the dollar'. We can definitely see the U.S. dollar being quite strong against emerging market currencies, and probably commodity currencies as well.

"It's hard to see much upside for the Aussie, kiwi or Canadian dollar, given what's happen with commodities and energy prices in general and sensitivity to risk appetite...if you're having liquidity problems on a currency like the Aussie, if there's concern there, then it's just multiplied for any emerging market currency."

MICHAEL FARR, PRESIDENT AND CEO, FARR, MILLER AND WASHINGTON LLC:

"It is a positive that the Fed appears committed to keeping the country?s financial plumbing from getting clogged.

"I don?t know exactly how the market reacts to this on the open but we?ve seen over the past week that all of this craziness can lead to liquidity issues that probably only the Fed can address.

"Ultimately, cheaper money lubricates the system but doesn?t get people back on airplanes or going to the office or to restaurants.

"I worry that U.S. rates fall into negative territory. I see that as a clear negative - especially for what it implies for economic growth over the next year or two."

DAVID R KOTOK, CHAIRMAN AND CHIEF INVESTMENT OFFICER, CUMBERLAND ADVISORS, FLORIDA:

"They fired a full broadside...Any additional policy response will have to be fiscal.

"My guess is another $200 billion to $500 billion needed quickly in order to offset damages from various shutdowns.

"Fed action is scaring folks because of unprecedented response. Markets see Fed replay of 2007-8-9 and are assuming a repeat of financial crisis is at hand."

KAREN PETROU, MANAGING PARTNER OF FINANCIAL ANALYTICS, INC.:

"The only way the Fed can quickly reach the 40% of American workers who enter poverty after just two lost paychecks and salvage millions of small businesses is to open facilities not just for the financial market, but also for hard-pressed households and small businesses.

"Waiting for liquidity ? even this much liquidity ? to funnel through banks to borrowers is waiting too long.

"Even if banks are willing and able to make safety-net loans, few, if any, have established programs to do so. The Fed has to make immediately clear what loans it will support and how; only then will money move fast to those who need it the most."

RICK MECKLER, PARTNER, CHERRY LANE INVESTMENTS, NEW VERNON, NEW JERSEY:

"For markets, most investors will take some solace in the fact that everyone is rowing in the same direction now both on fiscal and monetary policy. It is something that is definitely needed.

"The issue for investors that still remains is that the virus? economic impact is still not known, if this is a one-month event or if this is a one-year event, and how deep the cutback in consumer spending is going to be.

"In some ways this is preemptive, it?s try to get ahead of the curve. But I still think, particularly after this weekend, where most people saw just how much activity stopped, there are still going to be concerns that it could be a deep recession from this. It may be short, but it could be pretty deep."

JUAN PEREZ, SENIOR CURRENCY TRADER, TEMPUS INC., WASHINGTON:

"Clearly the Fed feels that what the governments are doing are inadequate and not enough. So they're throwing everything they can at this situation. But it's going to be really volatile when markets open. The dollar will swing wildly. We'll just have to see."

KARL SCHAMOTTA, CHIEF MARKET STRATEGIST, CAMBRIDGE GLOBAL PAYMENTS, TORONTO:

"This is the Fed?s 'whatever it takes' moment.

"Cutting rates to zero, launching $700 billion in QE, and opening swap lines in coordination with other major central banks are important steps toward smoothing the market dislocations that are putting the global economy at risk.

"After the initial shock and awe fades this evening, the message that central banks are working in concert to flood the system with liquidity could help reduce volatilities in FX markets.

"A risk-on rally looks increasingly possible, particularly if political leaders follow through on building support for fiscal stimulus measures."

MICHAEL O?ROURKE, CHIEF MARKET STRATEGIST, JONESTRADING, STAMFORD, CONNECTICUT:"This is an indication that the central bank is very scared about the environment we?re in. If there is a sharp rally, I wouldn?t be surprised if we see investors sell into it. The policy response is so strong, it?s likely to spook investors.

"Now they?ve expended all their ammunition. The question is, from a market perspective, have things clearly settled down? And they haven?t. They would?ve been better off waiting until the meeting on Wednesday. Most of their responses have been the wrong thing at the wrong time."We?re facing here the loss of credibility of the central bank from a market perspective...When the investor community loses faith in the Fed, that?s when the market gets very dangerous."

ROBERT PAVLIK, CHIEF INVESTMENT STRATEGIST, SLATESTONE WEALTH LLC, NEW YORK:

"They must really be scared. To do that in one fell swoop is really quite shocking. They pulled out whatever weapons they had and my sense is, I think it may help initially, but I don?t think it goes much further because this is still a developing issue...They used up basically all their ammunition and we?re down to sticks and stones.

"My sense is that the market may like it and may see a little bit of a rally but as you delve deeper into it, this is going to go on for a while, because we don?t have the tests that we need, we don?t have a vaccine, we don?t have a cure...I have gotten more concerned about the impacts to the economy."

QUINCY KROSBY, CHIEF MARKET STRATEGIST, PRUDENTIAL FINANCIAL, NEWARK, NEW JERSEY:

"What this suggests for the market is the Fed is serious, the Fed is targeting the liquidity in the credit markets and Treasury markets and trying to make certain that they operate without dislocation.

"There were dislocations with the Treasury markets, we know that. There were dislocations in other parts of the market. What the Fed is clear about is they are monitoring this.

"The question that has come up and has been hovering over the Fed is whether or not they include commercial paper. That of course is most likely. If they see any pressure in the commercial paper market they will introduce that as well.

"We have to remember that (Former Fed Chairman) Ben Bernanke not only bought 10-year Treasuries, he also bought mortgage backed securities. All I'm trying to say is the Fed can include whatever they want in whatever they buy."

IAN SHEPHERDSON, CHIEF ECONOMIST, PANTHEON MACROECONOMICS:

"In one line: Great news, but not enough on its own.

"We have been urging this action for some time and we?re very happy that the Fed did not wait until Wednesday?s meeting. Time is of the essence. Lower rates and QE should, other things equal, boost all asset price, depress the dollar, and boost money supply growth.

"Other things are not equal, though, and we think the Fed has acted now to try to get ahead of what likely will be terrible news on the spread of the virus, both inside and outside the United States, over the next couple of weeks.

"The lesson of Hubei and Korea is that lockdowns and social distancing measures take two or three weeks to bring about a clear downshift in case trajectory, with deaths then following."

"The Fed can?t do all the work itself. Congress has no choice but to pass the House bill, or something like it, and then immediately start work on a much bigger bill to push cash at small/medium-sized businesses, the self-employed, and households.

"Bailouts for airlines and parts of the hospitality business are inevitable."

PHIL ORLANDO, CHIEF EQUITY MARKET STRATEGIST, FEDERATED HERMES IN NEW YORK:

"On the interest rate side they've used most of their gunpowder. They also announced they'd inject $1.5 trillion into the banking system.

"What the market has been waiting for is the demonstration of some leadership out of Washington. We're getting it from the Fed and are on the verge of getting it from Congress and the Trump administration.

"The other piece is that the Senate needs to vote on what Pelosi and Trump agreed on Friday night, they'll possibly vote as early as tomorrow. If the market drops, McConnell will then vote for it.

"What we need to see additionally is the trajectory of the virus. We're getting the Washington policy response, but we have to see we're making progress on combating this virus."

SUBADRA RAJAPPA, HEAD OF U.S. RATES STRATEGY, SOCIETE GENERALE, NEW YORK:

"I?m surprised that the initial reaction coming out of Asia is somewhat muted, but I think it?s too early to get a good sense of how the market will react.

"I think markets are looking for more coordinated central bank action in the Asia session.

"The initial reaction in the markets seems to be somewhat positive, we?ll have to see how far bond yields decline. You have to assume some of the pressure we?ve seen in the spreads will start to ease.

"We?ll have to wait and see how markets react tomorrow."

(Compiled by by Ira Iosebashvili. Reporting by Lewis Krauskopf, April Joyner, Alden Bentley, Chuck Mikolajczak, Ross Kerber, Sinead Carew; Michelle Price; Gertrude Chavez-Dreyfuss; Saqib Iqbal Ahmed and Tom Westbrook. Editing by Clarence Fernandez)