Bank of New York Co. said Thursday it filed applications with the  Federal Reserve Board and the Massachusetts state banking board to double   its investment in State Street Boston Corp., to 9.9%.   
The New York bank acquired its current 4.99% in the third quarter of  1995, said Paul J. Leyden, senior vice president of investor relations. 
  
While Bank of New York made the common disclaimer that its move is "for  investment purposes," it is sure to fuel speculation about a closer   alliance if not a full-fledged merger. The companies have been linked in   merger speculation because of their strengths in securities processing and   potential economies of scale.       
David Berry, director of research at Keefe, Bruyette & Woods, said  securities processing, essentially 100% of State Street's business, will   produce about one-third of Bank of New York's net income this year.   
  
Mr. Berry said he "does not take at face value" that Bank of New York is  only interested in an investment. Though the bank has had 5% stakes in   regional banks such as Shawmut National and Midlantic, Mr. Berry suggested   a $500 million position in a company as profitable and prominent as State   Street is "higher profile" and qualitatively different.       
At the same time, Mr. Berry said if Bank of New York covets an  acquisition but it is not consummated, it would still be satisfied with its   investment.