Fidelity Investments, the country's largest mutual fund company, has  unloaded nearly half of its stake in North American Mortgage Co. over the   past three months amid rising interest rates.   
The higher rates appear to have clouded investors' perceptions of North  American's growth prospects, even though its loan originations have   continued to show gains over weak 1995 volume.   
  
Fidelity's trades took place from Feb. 13 through April 25, during which  time it sold 46.6% of its position in the Santa Rosa, Calif.-based mortgage   lender. The shares sold were worth about $15 million at the start of the   period.     
Of North American's 15.1 million outstanding shares, Fidelity owned  4.59%, or 693,700 shares, on April 25, according to filings with the   Securities and Exchange Commission. Before it began reducing its holdings,   Fidelity owned 8.5%, or 1.3 million shares.     
  
As Fidelity dumped the North American shares, their price fell from  $21.25 to $17. And by May 2 the price had fallen to $15.75, a 52-week low.   Meanwhile the interest rate on 30-year fixed-rate mortgages jumped by more   than three-quarters of 1%.     
By contrast, Countrywide Credit Industries, the No. 1 independent  mortgage company and with a much larger shareholder base than No. 2 North   American, has experienced little runoff of institutional investors, with   only minor defections so far this year. Its recent stock price of $22 was   about midway between its high and low for the last 12 months.       
The large selloff in North American by such a heavyweight investor  spurred some observers to question the lender's outlook. 
  
"Whenever Fidelity sells, I get a lot of calls from people who want to  know 'What gives?'," said Gareth Plank, a mortgage industry stock analyst   at UBS Securities, San Francisco.   
"Fidelity's known exposure to the bond market makes it more sensitive to  equity positions that also carry interest rate sensitivity," Mr. Plank   said.   
Geoffrey H. Bobroff, an East Greenwich, R.I.-based consultant, said  Fidelity's move away from North American raised an interesting question:   Why would Fidelity sell a mortgage company stock if it believes interest   rates will drop, as Fidelity's bond purchases suggest?     
At least one other investor took advantage of Fidelity's stock sale,  according to an SEC filing. 
  
Omega Advisors Inc., New York, a private investment firm bought 6.2% of  North American's outstanding stock from April 24 through May 3. The firm is   managed by Leon G. Cooperman, a former partner at Goldman Sachs & Co.   
"We bought the stock in the area of $16 or $17, and we believe it's  worth substantially more," Mr. Cooperman said. He said he believes the   company's servicing portfolio is worth $20 a share, and its origination   capability is worth $3 to $9 a share.     
Terrance Hodel, North American's president and chief operating officer,  said that the company had an ongoing dialogue with Fidelity, and that he   thinks the selloff was a reaction to the movement in interest rates in the   last few months.     
"Our stock is not heavily traded, so when people with heavy positions  trade, the stock price moves," Mr. Hodel said. He declined to comment on   Fidelity's sale of North American stock.