In spite of a jumpy market, the initial public offering (IPO) deluge continues. On the Nasdaq, Chinese technology services educator Tarena International priced 15.3 million shares at $9, in the middle of the $8 to $10 range. Separately, drug delivery systems provider Corium International priced 6.5 million shares at $8 —way more than the 5.5 million shares expected but below the price talk of $10-$12.

Two big ones pricing tonight: Grubhub (GRUB), the leading mobile platform for restaurant pick-up orders, is looking to price 7.0 million shares at $23-$25. Grubhub is a mere $165 million deal.

The really big offering comes by way of IMS Health Holdings, looking to price 65.0 million shares at $18-$21. They are one of the biggest online healthcare data managers in the world, with drug and insurance companies as clients. They are trying to figure out what is happening with patient usage of their products.

Think of IMS as a cross between Big Data, cloud computing, and healthcare: they give data on your drug use, hospital use, to the companies. This is a HUGE deal, well over $1.2 billion. This is a strong business that generates a lot of cash flow. This deal is being led by TPG and Leonard Green.

There are already signs the underwriters are getting more cautious. Look at digital ad firm Rubicon Project (RUBI), which priced yesterday at $15, the low end of the $15-$17 range. Still, they opened 20 percent higher, and ended up 33 percent.

It illustrates how underwriters are being cautious. The peer group--led by Rocket Fuel (FUEL)--has been moving down. So underwriters are telling investors to be cautious. In other words, the market is correcting to get to those post-IPO returns.

Markets have extended their rally. Part of the rationale, the fundamental investors keep telling me, is a belief that the U.S. economy will show improvement this spring after a brutal winter. The March ADP private payrolls report on Wednesday was a bit soft, but there was a significant upward revision to the prior month.

Meanwhile, overseas is busy. Chinese Li Keqiang Premier pledged to speed up railway and housing construction. The Premier again re-iterated a commitment to 7.5 percent growth.

That's big: many analyst thought it would easily slip to 6 percent or worse this year, and the Chinese would not have the stomach for additional stimulus. Thy are also considering extending tax breaks to small businesses. However, this is also a major problem for China's central bank: should they ease rates to stimulate growth? There is already considerable worry about credit risk.

The fell after European Central Bank (ECP) President Mario Draghi said the central bank has discussed using quantitative easing, or the money pumping employed by the Federal Reserve, in an effort to boost the economy. "The Governing Council is unanimous in its commitment to using all unconventional instruments within its mandate in order to cope effectively with risks of a too prolonged period of low inflation," said Draghi.