Federal regulators seized Washington Mutual (WM) on Thursday evening and sold most of the assets to JPMorgan Chase (JPM) in the largest bank failure in U.S. history, which had been precipitated by a wave of deposit withdrawals.

The Federal Deposit Insurance Corp. said on its Web site that all deposit accounts and loans from WaMu, a $307 billion thrift, had been transferred to JPMorgan, which agreed to pay $1.9 billion for the banking operations. However, JPMorgan said that it was not taking ownership of the holding company.

The federal Office of Thrift Supervision noted that "the change will have no impact on the bank’s depositors or other customers.  Business will proceed uninterrupted and bank branches will open on Friday morning as usual." Also, because JPMorgan bought the bank operations, there will be no impact on the FDIC's bank-insurance fund.

WaMu reportedly had significant trouble finding a buyer -- and indeed, couldn't find a buyer until after it went under -- but on a conference call late Thursday, JPMorgan sounded like anything but an unwilling partner.

"We don't know and we don't care" what other bids may have been for the operations, a JPMorgan executive said. "We bid to win."

JPMorgan said Thursday evening that it plans to offer $8 billion of its common stock for sale to the public.

While other recent transactions have been viewed as shotgun weddings carried out hurriedly, JPMorgan said that wasn't the case this time around.

"We spent an awful lot of time going through an awful lot of detail," one of the executives said on the call. Some later said that around 75 employees had been involved with the evaluation of WaMu.

JPMorgan expects the deal to be immediately accretive to earnings, and said that its financial estimates were quite conservative.

Interestingly, JPMorgan indicated that the proposed economic-rescue plan didn't factor into the decision to make this deal.

"We're in favor of what the government's doing, but we're not relying on what the government's doing" regarding plans for the economic bailout package, a JPMorgan executive said on the call. "We would have done it anyway."

That tone contrasted in particular with Warren Buffett's observations after his Berkshire Hathaway (BRK.A) bought a stake in Goldman Sachs (GS). Buffett intimated that he was betting on a bailout in doing the deal, and that he might even regret taking the stake if a rescue package didn't pass.

Earlier Thursday, it had been reported that WaMu was struggling to find a buyer, and had expanded its list of prospective buyers to include private-equity firms. WaMu has been under duress for some time, and its mortgage holdings in particular have been reported to be quite toxic.

On Wednesday, Standard & Poor’s had slashed WaMu’s rating to Ccc, eight levels below investment grade, following the example of Moody's, which had downgraded the company days earlier.

The OTS said in its press release that "customer questions regarding (WaMu), including questions about federal deposit insurance coverage, should be directed to the FDIC at 1-877-ASK-FDIC.  WaMu customers with questions can also call the bank's service center at 1-800-788-7000."

The stock fell nearly 30% on Wednesday, and on Thursday fell another 25% to $1.69 a share.

WaMu's rival Wachovia (WB) was having a tough time on Friday morning, with indications surfacing that the markets think it could be the next to go under. Reuters reported that  credit-default swap spreads in the financial sector widened significantly in the wake of WaMu's failure, with Wachovia's making a particularly big move.