Triangle is offering $41 a share for National Can.

New Brunswick, N.J.-based Triangle Industries reported that it began a cash tender offer worth about $420 million for the larger National Can, which already is the subject of two competing bids. Chicago-based National Can has more than 10 million shares outstanding. A National Can spokeswoman said company officials had not seen Triangle’s offer, which is $1 a share higher than a bid last month by National Can’s management for a majority of the company’s stock. The management offer was made to counter a buy-out proposal made a year ago by Miami financier Victor Posner.