Activist shareholders are pressing two Northeast thrift companies to  sell. 
New York investors Thomas F. Gillen and Donald B. Jennings lambasted the  management of Firstfed America Bancorp in Swansea, Mass., in a letter dated   June 30 but released late last week.   
  
In the first quarter, $1.3 billion-asset Firstfed posted a return on  assets of 0.58% and a return on equity of 8.13%, according to the Federal   Deposit Insurance Corp.   
"Unless returns of 1% or higher on assets and 15% or higher on equity  can be achieved, an investment banker should be retained to explore the   sale of the franchise," wrote the investors, who together own about 61,000   shares of Firstfed's stock, less than a 1% stake.     
  
In an interview, Mr. Gillen said that he and Mr. Jennings plan to  express their concerns at Firstfed's annual meeting on July 29. Robert F.   Stoico, chairman and chief executive of Firstfed, did not return calls   seeking comment Friday.     
Meanwhile, activist investor Seymour Holtzman has renewed his campaign  against Ambanc Holding Co. in Amsterdam, N.Y. His letter to management last   Friday blasted the $730 million-asset company's recent announcement that it   is no longer considering a sale.     
Mr. Holtzman, who owns about 5.8% of Ambanc's outstanding shares, wrote  that a shrinking market clouds the company's future. 
  
Last year, Ambanc agreed to make Mr. Holtzman a director; in return, he  agreed to support an acquisition the company was trying to complete. 
John M. Lisicki, Ambanc's president and chief executive, did not return  calls. In a press release last week, he said the company had decided that   "our stockholders will realize the greatest returns through continuing our   operation as a dynamic, community-based bank."     
Mr. Holtzman said he intends to take his concerns to the stockholders.  "There is no doubt in my mind that shareholders should and will send a loud   and clear message to the board," he said.