TOKYO (Reuters) -Nissan Motor shares jumped as much as 6% in early Tokyo trading on Friday after Japan's Diamond Online magazine reported that activist investor Oasis Management had taken a stake in the automaker.

Nissan's shares had also jumped on Tuesday after a filing showed an entity related to activist Effissimo Capital Management had taken a stake in the company.

Diamond magazine cited an unnamed person as saying Oasis had taken a stake in Nissan before Effissimo. The size of the stake and when the shares were bought were not clear, the report said.

An Oasis representative declined to comment on the report.

Shareholder activism has gained traction in Japan, where international and domestic investors are demanding firms to improve corporate governance and capital allocation at a record pace, also helped by regulators' guidance.

Nissan last week issued a profit warning and said it would slash 9,000 jobs and a fifth of its global manufacturing capacity amid a sales slump in its two biggest markets, China and the United States.

Its shares were last up 4% at 426.7 yen ($2.73), compared with a 1.2% advance on the benchmark Nikkei index. The stock is down 35% from its high this year.

($1 = 156.5400 yen)