Two new stocks debuted on Wednesday with opposing performances, as Banco Santander's Brazilian unit started with a whimper, while insurance risk specialist Verisk Analytics Inc kicked off with a bang.

Shares of Santander Brasil fell as much as 2.9 percent on their first day of trading following a record initial public offering, while Verisk surged 29 percent after its IPO priced above the expected range.

Executives of Santander Brasil sought to focus on the fact that it raised 14.1 billion reais ($8.05 billion) with its IPO in Sao Paulo and New York -- the largest ever in Brazil and the biggest in the world since March 2008.

The timing could not have been better, Fabio Barbosa, Santander's chief executive for Brazil, said at a news conference with executives from the Sao Paulo stock exchange, citing signs of recovery in the Brazilian economy.

But any investors hoping to profit by quickly flipping their shares were sorely disappointed.

The shares came under pressure because of both the size of the offering and the price, which put Santander Brasil's valuation higher than those of some Brazilian rivals, traders said. The bank's price-to-earnings ratio of 17 times was above the market average of 15, said Joao Augusto Frota Salles of consulting firm Lopes Filho in Rio de Janeiro.

The offering was very large and demand would have to be compatible with that, Salles said. You'd have to find enough investors that didn't enter the IPO to want to buy the stock today for the price to rise, and that's not what's happening.

The shares were down 2.3 percent to 22.95 reais in Sao Paulo, Brazil's financial capital.

New York-traded shares of the bank, formally known as Banco Santander (Brasil) SA, were down 3.1 percent at $12.98. The Brazilian IPO priced on Tuesday at 23.5 reais, while its U.S.-traded shares priced at $13.50.

The offering will add 1.43 billion euros in capital gains for the bank's Spanish parent, Santander said in Madrid.

Verisk jumped 24.4 percent to $27.36 after it completed a $1.88 billion IPO, the largest by a U.S. company since March 2008, when credit card operator Visa Inc went public.

Verisk shares priced at $22, above their estimate range, and were trading at $27.50 in afternoon dealings. The company, which collects actuarial and underwriting data related to U.S. property and casualty insurance risks and was owned by a group of leading property and casualty insurance companies, will get none of the proceeds in the IPO.

Verisk Chief Frank Coyne told Reuters that the company would hope to have a follow-on share issue once it is allowed to do so.

BRAZIL IPO OUTLOOK

Brazil's economy, the largest in Latin America, has emerged from a brief six-month recession and is expected to expand as much as 5 percent in 2010, which should boost demand for consumer finance and corporate loans.

Optimism over Brazil's growth has also thrust the country to the forefront of global capital markets. Two of the world's top three IPOs this year were by Brazilian companies, the Santander sale on Tuesday and the VisaNet offering in July.

The Santander offering also surpassed the IPO by China State Construction Engineering Corp <601668.SS>, which raised $7.3 billion in July.

The Santander IPO capped months of torrid activity in Brazil's stock market, which has had about 21.8 billion reais in share sales since late June. The offering also benefited from a growing appetite for emerging market securities that has helped push the Bovespa index <.BVSP> 68 percent higher so far in 2009.

Exchange operator BM&FBovespa is expecting strong IPO activity in the first half of 2010 as companies revive plans that had been shelved earlier this year because of the turmoil in global financial markets, Chief Executive Edemir Pinto said.

The Santander IPO is a victory for the local capital markets and it's proof of our capacity to host the largest offerings in the world, Pinto said. We are the hottest emerging market in the world at the moment.

($1=1.762 reais)

(Additional reporting by Guillermo Parra-Bernal in Sao Paulo and Phil Wahba in New York, editing by Gerald E. McCormick)