Complex sentence: Quotron's success attracted the attention of Robert S. Sinn, who observed its disadvantages: it could only give a last price; the opening price, high and low for the day, and volume of shares sold were not available.
Split into simpler sentences: Quotron's success attracted the attention of Robert S. Sinn, who observed its disadvantages: it could only give a last price. The opening price, high and low for the day, and share volume were not available.