FRANKFURT, Oct 14 (Reuters) - SLM Solutions :
* Says activist investor Elliott has increased its stake in the 3D printer manufacturer to 20 percent from 16 percent.
* Says increase in holding effective Oct. 11.
* Regulatory releases show Elliott started building a stake in SLM shortly after General Electric announced plans to buy the company on Sept. 6.
* GE's offer runs to Oct. 24 and is conditional upon a 75 percent acceptance rate.
* Shares in SLM stand at about 41 euros, well above GE's 38-euro-per-share offer. (Reporting by Maria Sheahan; Editing by David Goodman)