KLM Threatens Suit Over Northwest Plan: KLM Royal Dutch Airlines, which owns about 20% of the Minnesota-based carrier and could buy more, may sue to prevent Northwest Airlines from capping ownership by any shareholder at 15% to 20%. The proposal, filed Oct. 26 in a registration statement with the Securities and Exchange Commission, is up for approval Nov. 16 at Northwest Airlines’ board meeting. KLM has an option under its stockholders agreement to buy more shares in 1998, which would bring its voting interest to 25%--the limit for non-U.S. interests under federal law. The Dutch airline would oppose Northwest’s plan if it hurt KLM’s ability to exercise that option, according to the SEC filing. Under Northwest’s proposal, KLM would be forced to sell an equal number of existing shares to stay below the cap.