Less than a month after Southwest Securities Group Inc. of Dallas announced a plan to buy Matrix Bancorp in Denver, the deal has been aborted.

Officials at $1.3 billion-asset Matrix and the investment bank Southwest Securities said Friday that they have decided instead to "proceed independently." In an interview, Matrix vice chairman Mark Spencer said the deal collapsed because the two sides could not agree on how the companies would be run after the merger.

"There was no due diligence. There were no extensive negotiations - we were just not able to come to terms," Mr. Spencer said.

Southwest, which had hoped to sell its brokerage products to Matrix's customers, announced July 13 that it had signed a letter of intent to buy the banking company for about $100 million of stock.

News of the deal's collapse sent Matrix's stock into a free fall. The stock, which had soared in the days after the deal was announced, was trading at $7 a share early Friday, down 34% from Thursday's close.

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