Washington Mutual is known for its no-thrills, no-fees, unconventional banking with a hip, neighborly feel. Its nickname? WaMu. Its tag line? Whoo hoo!

But the recently collapsed bank's new owner, JPMorgan Chase, is known for being big and conservative — two very different vibes. Its advertising preaches value and security.

The newly combined company has its work cut out for it, experts say, if it wants to blend the two different brands and keep its customers.

It's not clear yet what will happen with the brands, but WaMu's ads will no doubt have to change to temper its feisty image, which has mocked staid rivals such as Chase, said Jean-Pierre Dube, a marketing professor at the University of Chicago Graduate School of Business.

"It strikes me as incompatible because JPMorgan Chase represents precisely what Washington Mutual was critiquing and attacking in their advertising," he said yesterday.

Seattle-based Washington Mutual Inc. was seized Thursday by the Federal Deposit Insurance Corp., which then sold the thrift's banking assets to JPMorgan Chase & Co. for $1.9 billion. The collapse marked the nation's biggest bank failure. The sale makes JPMorgan Chase the second-largest bank in the U.S., after Bank of America Corp., which recently bought Merrill Lynch.

JPMorgan Chase said the acquisition will give it 5,400 branches in 23 states, and that it plans to close less than 10 percent of the two companies' branches. But little has been said about the brand marketing.

The problems at WaMu had apparently been building for some time as the company got caught up in the subprime mortgage business, whose troubles spread across the entire industry.

But those issues weren't evident in WaMu's peppy ads, which portrayed a lively, unconventional banking environment.

Some of the ads positioned WaMu as a happier, freer alternative to its competitors. The "anti-stodgy banker" campaign launched in 2006 featured older men in suits who didn't like WaMu's perks such as free checking for life and free ATM cash withdrawals.

New ads feature the slogan "Whoo hoo!" and show people fantasizing about driving cars and being in kangaroo pouches, with their newfound financial freedom.

In an era that is seeing so much financial upheaval, JPMorgan Chase may want to drop those types of ads, Dube said. Tried and true may be a better route, he said.

"Washington Mutual had a radical message in their advertising, and given how hard they fell, it seems like maybe there's something to be said for the old, conservative, traditional banking model," he said. "The stodgy old businessmen may not be fun and give you deals, but they give you value. They give you security."

Value is also a big part of the WaMu package, said Rita Rodriguez, chief executive for the U.S. division of The Brand Union, a firm that helps companies create brand identities. She said the company was an early trendsetter of positioning itself as a friendly bank that was accessible and focused on helping customers.

Rodriguez said JPMorgan Chase may not want to completely abandon WaMu's marketing because of its personal approach.

"The challenge they will have from a brand perspective, is whatever happened with WaMu there will be people that still have strong associations to the brand and the challenge will be, what does and how does JPMorgan Chase integrate WaMu from a brand level," she said.