There's no question in the minds of competitors in the mid- and South Atlantic states that NCNB Corp. plans to establish a banking network stretching from Baltimore to Miami. The only question that remains is, how long will it be before the big Charlotte, N.C., bank company becomes a dominant player in the Washington-Baltimore region?

NCNB has clearly demonstrated over the past year that it doesn't plan to let other big regionals, such as Sovran Financial Corp. and MNC Corp. (formerly Maryland National Corp.), get too big a head start in the Washington region.

First NCNB acquired Prince William Bank in Dumphries, Va., last year and then agreed to buy Baltimore's Centrabank.

Compared with acquisitions in the region by most of the big Virginia bank holding companies and Maryland National's merger with American Security Bank of the District, however, NCNB's northern forays have been relatively minor.

Although widely known for its aggressive acquisition strategy, which made it the biggest bank company in the Southeast, NCNB's low-keyed approach since venturing north of North Carolina conjures up the image of a sleeping giant. That's likely to change dramatically in the not-too-distant future, however.

Three clearly identifiable trends have emerged in the nearly two years since interstate banking laws in the Washington region became effective. A fourth should become apparent three weeks from now when phase II of Maryland's interstate banking law goes into effect. The new law will allow entry into the state by bank companies from North Carolina and 10 other states under reciprocal legislation.

NCNB announced last week that the Federal Reserve Board has approved its pending merger with Centrabank. The merger is expected to be completed on July 1, signaling the start of the fourth significant interstate banking trend in the region.

The first trend started with enactment of reciprocal interstate banking laws in the region, which set off a merger binge in which Virginia bank holding companies acquired banks in the District and Maryland. Then Maryland opened the door wider to interstate banking by approving special legislation permitting limited entry into the state by big Northeast banks. A third trend can be seen in the dozen or more applications from out-of-state firms, primarily from the Northeast and Midwest, that want to open banks in the District.

In the wake of those developments then, NCNB obviously concluded that it was necessary to establish what one banking industry analyst described as "reasonable staging points in the Maryland and Virginia suburbs" of Washington.

Having done just that in Virginia last year, NCNB has ignited no small amount of curiosity in that state's banking industry. Indeed, Sydney Bailey, Virginia's savvy banking commissioner, wondered aloud during a panel discussion on interstate banking last week about NCNB's intentions in his state.

Bailey probably won't know the answer until well after NCNB makes known how it plans to capitalize on its Centrabank acquisition.

In the meantime, it seems clear that NCNB's strategy for this region is far more conservative than the policy it employed in its merger binges in South Carolina, Georgia and Florida. Unlike other holding companies that have acquired banks in this area, NCNB has maintained a tight grip on its purse strings. Whereas banks in the region generally have been sold for more than twice their book value, Centrabank will fetch much less.

NCNB agreed to pay $8.7 million in cash, and it will issue warrants allowing Centrabank shareholders to purchase up to 350,000 shares of NCNB stock. Even with Centrabank's book value at $12 million, and NCNB's stock at $23.62 1/2 (yesterday's closing price), the merger transaction would be less than twice Centrabank's book value. Buyers have paid much more for considerably smaller banks in the region.

"We will continue to be conservative in the multiples we pay" for banks, declared Dick Stilley, assistant vice president, corporate communications at NCNB. "We are not going to take large dilutions."

As the biggest bank company from Florida to Pennsylvania, NCNB, with assets of $26 billion, is large enough not to feel threatened any longer by larger institutions.

Given NCNB's goal of operating a retail banking network from Baltimore to Miami, "You can expect to have more than just two branches in Virginia and eight in Baltimore," Stilley said.

NCNB's conservative merger strategy rules out immediate ownership of an established large branch network in the Baltimore-Washington-Richmond corridor. Its low-budget acquisitions give it access, nonetheless, to the same lucrative market for which its major competitors paid so dearly.