Stratasys Ltd. NNDM, -0.63% announced Wednesday that its board had again rejected a sweetened Nano Dimension Ltd. NNDM, +2.16% offer made on Tuesday. The board said the offer Nano Dimension increased its offer from $24 to $25 per share, in order to buy between 31.9% to 36.9% shares of the company. Since May, the two have been in a battle to buy Stratasys – a 3-D printer maker – with 3D Systems Corp. DDD, +0.73%. The board warned shareholders that they could lose up to 40% of their shares if they participate in the tender and become minority shareholders. Stratasys shares were up 1% in premarket trading and have gained 80% this year. The S&P 500 , SPX, +0.71%, has gained 18.6%.