Complex sentence: In 1992, Timber Hill began trading at the Swiss Options and Financial Futures Exchange, which merged with DTB in 1998 to become Eurex; at this time, Timber Hill had 142 employees.
Split into simpler sentences: In 1992, Timber Hill began trading at the Swiss Options and Financial Futures Exchange, which merged with DTB in 1998 to become Eurex. At this time, Timber Hill had 142 employees.