Tin foil hat time... For a microcosm of how virus reporting numbers can skew perception, one need only look at the recently events aboard the Diamond Princess cruise ship.
On Feb 4, the ship was officially quarantined with 10 confirmed cases of the virus onboard. By the 6th there were an additional 31 cases, By the 9th an additional 66 cases, on the 11th 39 new cases, on the 15th 67 new cases and today 70 new cases.
At first glance one would conclude "ok, so the virus is spreading on a linear curve but doesn't seem to be blowing up like crazy"... but the overlooked fact that is that up until now, only 1,219 of the 3,700 onboard have been tested. That's roughly only 100 ppl tested per day which severely caps your sample rate. The reality is nobody knows how many ppl were already infected when they started the tests, and until everybody's been tested it's silly to even venture a guess at the rate of propagation based on incomplete results.
Newly confirmed cases/day in Hubei province has also been hovering around the same rate at +1k/day... even dropping a bit lately. But like the cruise ship, my guess is this steady number is limited by how many tests they can conduct on a given day.... and in a macabre twist, the drop in confirmed cases is more likely due to a drop in the # of tests given/day now that 1,700 health workers are infected and more than half a dozen have died.
If you extrapolate the results from the cruise ship of 1,219 tests returning 355 positive, that's about 1 in 3. So given the 70k or so confirmed cases, it's reasonable to assume that Hubei has conducted about 233k tests so far.
Therein lies the problem... Hubei province has about 58.8 million people. So up until now only 0.4% of the population has been tested. And this is assuming an infection rate in quarantined conditions. China has been reluctant to divulge numbers on just how many tests are given and it's easy to see why. The sample rate not only caps the number of new confirmed cases, it also caps the number of deaths attributed to the virus since only ones from confirmed cases count.
Wall street isn't dumb. If I can see this cognitive dissonance then surely they do as well. Some have postulated that the virus is NBD and China will return to economic normalcy by April... I think that's kind of ludicrous to assume at this point. I'm expecting a serious risk off move by the end of the month... something like 3400 -> 3300 in a week.