BALTIMORE -- The value of assets held by the 22 largest bank holding companies in the Baltimore-Washington corridor increased $59 billion in the last two years, according to a study released last week.

"Changes in interstate banking legislation have undoubtedly resulted in a profound and positive impact on the growth of financial institutions in the Baltimore-Washington region, resulting in increased lending capacity and broadened customer services," said P. Wesley Foster Jr., chairman of the Baltimore-Washington Regional Association, which produced the study.

The study, called "Financial Resources in the Baltimore-Washington Common Market," indicated that the 22 holding companes -- which each have at least $250 million in assets -- have combined assets of more than $129 billion, compared with $70 billion in 1985.

The study found that the number of thrifts with assets exceeding $250 million rose from 23 to 28, and their total assets increased from $17 billion in 1985 to $26 billion this year.

"The depth and breadth of services offered by these institutions, coupled with the Common Market's rapidly expanding economy, are transforming the bimetropolitan region into an important financial center," Foster said.

The study also found the number of venture capital firms increased from 27 to 33, which now are capable of providing capital commitments ranging from $10,000 to $15 million.