Suburban Bancorp presented an impressive case earlier in the week as evidence of a strong performance last year.

Its stockholders, at least, appeared impressed by the slide show presentation by President G.J. Manderfield. Comparisons of performances of 16 banks in the region and national institutions with assets between $1 billion and $2 billion showed Suburban matched or surpassed its competitors in most categories measured.

At least, that's the story Suburban told stockholders.

But it was, in a way, the wrong audience. Suburban's stockholders in this instance were the true believers. They wouldn't have been there if they weren't.

Indeed, nobody complained about the company's earnings or overall performance. They already knew from quarterly and annual reports how well the company did last year.

Nevertheless, one stockholder summed up a feeling of frustration shared by others--and management, possibly--when he asked: "Why isn't the stock doing any better in the marketplace?"

Suburban's Chairman Robert F. Tardio had heard the same complaint before. "I think the only thing I can point out is nothing new, but some observations again," he replied.

The relative lack of enthusiasm for Suburban's stock, Tardio suggested, may lie in the fact that "the analysts who measure banks have probably put us in a third tier."

Tardio explained that the third tier would include smaller retail banks rather than the big money-center banks that comprise the first tier, or the large regional institutions generally considered second-tier banks.

Although it's close to becoming a $2-billion-asset institution, Suburban is smaller than most of the 16 regional banks with which it is compared. In the District, for example, Riggs National Corp. and American Security Corp. are already over $2 billion in assets.

The same is true in Suburban's primary market area in Maryland. The Bethesda-based bank holding company competes with the likes of the $4-billion-asset Maryland National Corp., the largest in the region; First Maryland Bancorp.; and Equitable Bancorp.

Nevertheless, bank analysts agree with Suburban that its performance when compared with those institutions is "impressive."

For example, composite data of 85 financial institutions with assets between $1 billion and $2 billion, compiled by Keefe, Bryette & Woods Inc., show their return on equity last year was 14.05 percent. A similar compilation of results from 16 banks in this region produced a figure of 14.30 percent compared with 15 1/2 percent for Suburban.

Stockholders learned futher from Suburban's performance chart that its return on assets was 1.19 percent compared with 0.98 percent for regional banks and 0.93 percent for the national group.

"Anything over one percent is considered good in this industry," Manderfield noted.

In a measurement of nonperforming assets to total loans, comparisons showed Suburban with 0.83 percent, regional competitors with 1.57 percent and a composite 1.92 percent for the national group.

"We do not anticipate that that 0.8 percent will go up" in the current year, Manderfield said. "If anything, it will go down."

Mindful that that has become a headache for some competitors in a worsened economy, Manderfield wryly observed, "This is one that's been getting a little bit of publicity in the press lately."

In reporting first-quarter earnings to stockholders, Suburban noted that its provision for loan losses decreased by almost 51 percent. It explained that the decrease "reflects improved loan portfolio quality and reduced net charge-offs as well as a higher allowance for credit losses as a percentage of outstanding loans."

Suburban is to be "congratulated" on its performance, a stockholder acknowledged but he wondered who has the answer to why the stock is selling in the $18 range in the over-the-counter market.

"I think one factor involved has been the limited communication between the bank and the financial community," said Eliot H. Benson, vice president and research director at Ferris & Co. Inc.

"I think they've kept their candle under a bushel--a metal bushel at that," Benson continued.

Suburban's record is "quite impressive," and its stock has begun to move up in price, he noted.

Still, "They've kept the lowest conceivable profile imaginable" compared with other major banking institutions in the area, Benson said. "I don't think there are that many brokers making a market in their stock."

"The syndrome, or scenario is pretty much the same for all regional banks" in terms of stock performance, observed Ernest C. Kiehne, director of research at Legg Mason Wood Walker Inc.

Concern over high interest rates, the budget and inflation have tempered interest in buying regional bank stocks, he added.

Suburban is one of the outstanding regional banks and, in time, could be selling around $30 a share instead of $18, Kiehne ventured.