Giant initial public offerings this week by Banco Santander (Brasil) SA and Verisk Analytics are likely to be followed by more outsized IPOs, but the mixed performance of the stocks shows selling future deals could be difficult.

Verisk, an insurance risk specialist owned in part by Warren Buffett's Berkshire Hathaway Inc, soared 24 percent the day after it was sold, while Santander Brasil edged down 3 percent in U.S. trading.

Another recent mega-IPO, Chinese videogame maker Shanda Games fell 14 percent on its first day of trading.

When IPOs perform poorly, subsequent share issues from the company can be harder to sell, as can other deals led by the investment bankers.

To be sure, the fact these IPOs are getting done at all indicates that the market has recovered over the last year.

Santander Brasil was an $8.05 billion deal, Verisk was $2.16 billion, and Shanda was $1 billion. Before these IPOs, total proceeds from U.S.-listed initial offerings for 2009 stood at just $6.33 billion.

And Wall Street underwriters seem confident that demand will continue to be strong.

There's still a lot of cash on the sidelines- we will see more and more mega-IPOs, said John Chirico, co-head of capital markets origination for the Americas at Citigroup.

The mega-IPOs drew in investors such as mutual funds, pension funds and hedge funds that gravitate toward larger deals. And because there have only been a few large IPOs of late, there is room in their portfolios for more, bankers said.

The recent IPOs have shown that there is intense appetite for jumbo-IPOs, said Lisa Carnoy, global head of equity capital markets at Bank of America Merrill Lynch.

But issuers and underwriters have to be cautious when pricing and setting an IPO's size, lest it fall in its debut, the bankers said.

Analysts had said prior to its IPO that Santander Brasil was not being priced at a discount to its peers. Shanda Games' first day fall was pegged in part to the 32.5 percent increase in the number of shares it was selling just days before the IPO.

Large IPOs in the pipeline include a $2 billion carve-out of the U.S. unit of Brazilian meat processor JBS, expected in January and a $1.15 billion IPO by hotel operator Hyatt Hotels. Discount retailer Dollar General Corp's $750 million IPO is expected by year-end.

COMING UP NEXT WEEK

The largest of two U.S.-listed IPOs on the calendar next week is by RailAmerica Inc, which is expected to raise $357 million and list on the New York Stock Exchange.

The Florida company owns and operates short line and regional freight railroads in North America, including 40 individual railroads with approximately 7,500 miles of track.

RailAmerica is owned in large part by private equity funds managed by a unit of Fortress Investment Group LLC which will still own 57.7 percent of RailAmerica stock after the IPO. It will price on Monday and trade the next day.

China Real Estate Information Corp, a provider of real estate information and consulting services, is set to price its $200 million IPO on Thursday and list on Nasdaq.

The company, a Shanghai-based unit of real estate services company E-House China Holdings Ltd, operates a database with information on developments in 56 cities in China.

The company plans to buy the online real estate business operated by Sina Corp, a Chinese media company which in turn would acquire a large stake in China Real Estate Information following the IPO. E-House will remain its parent company and controlling shareholder after the offering.

 (Reporting by Phil Wahba; Editing by Tim Dobbyn)