Consolidation across states lines and largely successful efforts by  many banks to get into new businesses seem to be increasing the   number of banking holding companies - even as the number of banks in the   nation continues to decline.     
According to an American Banker survey of the top 100 U.S. banking  companies, there were 1,283 bank holding companies as of   March 31 - 40 more than at the end of 1995. There were   only 828 on Dec. 31, 1990.     
  
From yearend 1995 to March 31, the number of banks dropped by 103, to  9,838. At the end of 1990 there were 12,347. 
Analysts said the steady increase in holding companies and  the corresponding decline in banks can be attributed   primarily to two factors: diversification and consolidation.   
  
The analysts noted that as banks diversify beyond straight lending and  deposit-taking and get into new businesses, such as leasing, they   require a holding company structure. Acquiring a bank in another state,   they added, often also requires a holding company structure.     
"If you want to do anything else, you have to do it through a holding  company," said Carol Berger, a bank analyst at Salomon Brothers Inc. "Most   nonbank activities require a holding company structure."   
Analysts said the large number of thrifts converting  to banking charters probably has helped to   boost the number of holding companies. They also noted that some   banks have set up multiple layers of holding companies, in order to put   individual banks acquired in other states under a single roof.       
  
The American Banker survey also found  a gap in size is emerging, and widening, between a   handful of big bank holding companies and the 1,225 others with assets of   less than $10 billion.     
The growing gap amply illustrates that there is room in the market for  big and small banks, but less and less room for midsize institutions,   analysts said.   
"People have been saying for years that midsize banks are the ones  feeling the most pressure from the consolidation in the industry," observed   Raphael Soifer, a banking analyst with Brown Brothers Harriman in New York.   
Large banks, he said, have economies of scale and can  offer a wide variety of products and services, while community   banks prosper because they have close ties to local business.   
  
"It's the ones in the middle which are too large to be true community  banks, yet too small to compete on a level playing field with giants that   are gradually merging with each other and being bought up by the bigger   fish," Mr. Soifer pointed out.     
Among the other findings:
*Merger activity, which rose sharply since midyear, continues to affect  the rankings of the top 100. Bank of Boston Corp. acquired BayBanks   Inc. on July 29; NationsBank Corp. announced on Aug. 30 its plans to   acquire Boatmen's Bancshares; and Crestar Financial Corp. of   Richmond, Va., announced Sept. 16 that it plans to acquire Citizens   Bancorp of Laurel, Md.         
Had all three of these mergers taken place before June 30, NationsBank  would have ranked fourth, with $232 billion in assets; Bank of Boston 15th,   with $60 billion in assets; and Crestar 31st, with pro forma assets of   $22.7 billion. Instead, NationsBank came in fifth, Bank of Boston ranked   16th and Crestar came in at 40th.       
*Assets held by the top 100 bank holding companies at midyear 1996 rose  7.84% to $3.45 trillion, or 63.7% of all assets held by banks. That's up   from $2.3 trillion at midyear 1991, or 49% of all banking assets.   
*Deposits at the top 100 banks increased 8.45% to $2.19 trillion, or to  57.7% of all bank deposits. 
*The top 100 employed nearly 1.2 million people at 35,555 branches,  compared to 1.16 million people at 33,299 branches in mid-1995. 
*Total capital ratios for the top 100 improved to 13.41% from 13.31% 12  months earlier.