No US monetary and fiscal policy can save the US stock markets.

Trump had pumped more money into the repo market by offering $500 billion in three-month repo operations, an additional $500 billion in one-month operations and another at least $220 billion in operations with durations of two weeks or fewer.

There was no liquidity issue in the first place as the repo rate didn’t shoot through the roof. Therefore, increasing the repo funding doesn’t help much and won’t stop the stock market from crashing.

http://sg-stock.blogspot.com/2020/03/why-did-us-fed-do-emergency-interest.html

Trump had also announced some fiscal policies but the stock markets still crashed.

We had stated that using monetary and fiscal policies won't do much to resolve a medical healthcare crisis.  However, the ensuing outcome of a medical healthcare crisis is a financial crisis.  Thus, if we can contain and resolve the virus outbreak, we don't have to worry much about the financial crisis later.

I don't see any way out for the US now except to wait it out.  Hopefully, a vaccine will be produced soon.  As usual, the US will restart its quantitative easing (QE) programme and keep its interest rates low to continue to pump money into the financial system and this will create an even bigger financial crisis in the future.

We had stated before how the QE affected the world using HK and SG as examples.

http://sg-stock.blogspot.com/2019/09/the-hong-kong-protestors-know-nothing.html

The investors such as fund managers are badly burnt this time because they have underestimated the covid-19 outbreak.  Why?

Let's take a look at 10-year yield first.

The 10-year yield (risk-free rate) is rebounding from its recent record low of about 0.30%.  In other words, the bond price is plunging now.  This doesn't auger well for the financial markets because this is the signal that the bond investors are cashing out to cover their losses in stocks and commodities.

The gold prices have also fallen from US$1700 to US$1500++ now.  (The investors are cashing out.)

Bitcoin prices have also fallen to US$5000 now. (The investors are cashing out.)

No market is spared from this bloodbath and this just shows how badly the investors are hurt by this malaise.