After largely abandoning investment banking in the aftermath of the 2000 tech-stock bust, regional bankers again are looking for ways to sell customers advice on deals as the mergers boom continues.

Following the lead of the industry's three big titans, two major commercial banks have bought small investment banks in the past year. Analysts see the start of a trend.

Wells Fargo & Co., of San Francisco, the nation's fourth-largest bank by market value, several weeks ago announced the purchase of Barrington Associates, a boutique investment bank in Los Angeles that specializes in advising midsize businesses with annual revenue of between $25 million to $1 billion. The deal's terms weren't disclosed; some bankers estimate the sale price of the 40-person shop at about $50 million.

The Barrington deal follows a similar move last year by PNC Financial Services Group Inc., of Pittsburgh, the nation's 14th-largest bank by market value. It bought Harris Williams & Co., a 110-person boutique investment bank in Richmond, Va., that is considered a leader in middle-market mergers-and-acquisition advisory work. The terms of the Harris Williams deal weren't disclosed. Profits at Harris Williams are up substantially since the acquisition closed in the fourth quarter of 2005, the bank says.

These deals mirror strategies pursued by the industry's biggest players -- Citigroup Inc., Bank of America Corp. and J.P. Morgan Chase & Co., Nos. 1, 2 and 3 in the U.S. by market value. Over the past decade, each has expanded to become massive financial institutions that can offer big corporate clients broad lending capabilities and investment-banking services like stock underwriting and merger advice, while collecting their cash deposits. The regional banks aren't looking to compete with the big players on a global scale, but want to offer more services to existing customers and attract new ones that are often ignored by the financial giants.

"What is happening is that the bundled-product model is coming more into the middle market," said Jim Lawson, a co-founder of Lincoln International, a Chicago midmarket investment bank with 100 bankers in the U.S. and Europe. "You will see more consolidation between M&A boutiques ... and financial institutions."

Analysts say other commercial banks that could seek out similar arrangements include U.S. Bancorp, BB&T Corp., Fifth Third Bancorp, Capital One Financial Corp., Comerica Inc., National City Corp., Regions Financial Corp., SunTrust Banks Inc. and Zions Bancorp.

Midtier investment banks like Jefferies Group Inc. and Piper Jaffray Cos., both publicly traded, often are discussed as possible targets for regional banks. But bankers and analysts say smaller, independent middle-market advisory shops without costly trading, sales and research staffs are more likely to receive overtures from a large regional bank, especially if they have international offices and knowledge of multiple industries. Such firms include Lincoln International, Sagent Advisors Inc., of New York, and Goldsmith Agio Helms, of Minneapolis.

The recent deals won't transform Wells Fargo or PNC. But they fill a void that many regional banks are learning they must plug to service the increasingly sophisticated financial needs of their base of small and midsize businesses.

Many of these mostly privately owned companies -- from a variety of industries, including aerospace and manufacturing -- find themselves seeking big chunks of capital to expand globally or advice on selling all or part of their operations to private-equity firms or other buyers, often overseas.

Executives at Wells Fargo and PNC say they will provide their respective boutique investment banks with financial heft and more products to offer clients. Still, in a nod to the cultural divide between commercial bankers and investment bankers, both banks say they will allow the boutiques to maintain their current names and continue to operate much as they did before being acquired.

Will such marriages work over the long haul? Commercial bankers have tried to buy instant investment-banking presence before, only to abandon those efforts when the mergers-and-acquisition market turned sour.

Several regional banks shuttered once-iconic boutique investment banks after the technology-stock boom went bust in 2000, including FleetBoston Financial Corp.'s Robertson Stephens, of San Francisco. That experience leaves many investment bankers and commercial bankers hesitant to hook up.

In this environment, however, many midsize companies aren't satisfied with their longtime regional banks simply lending them money, bankers say. With private-equity firms buying up more midsize companies, traditional loans and lockboxes aren't enough. Company executives and their private-equity backers want access to derivative products, interest-rate swaps, M&A advisers with global reach and many wealth-management options.

"You have to bank them like they are a big corporation," says William Demchak, PNC's vice chairman and head of institution banking.

One upside of this approach, commercial bankers say: By selling more fee-based financial services, they can make a tidy profit they otherwise mightn't earn by lending out money in today's competitive and difficult interest-rate environment. Regional banks that fail to adapt risk losing clients to hedge funds, private-equity firms and larger Wall Street rivals with more financial offerings and services.