Complex sentence: He moved back to Stockholm to start in 2004 IQUBE, which quickly grew into one of the largest private incubators in Europe with a portfolio of more than 100 companies.
Split into simpler sentences: He moved back to Stockholm to start in 2004 his next venture, IQUBE. IQUBE quickly grew into one of the largest private incubators in Europe with a portfolio of more than 100 companies.