Complex sentence: While CEO, Jain's personal worth rose from almost one billion dollars in 1999 to USD $2.2 billion in 2000 when, at the height of the dot-com bubble, he was ranked 121 on the Forbes 400 Richest Americans.
Split into simpler sentences: While CEO, Jain's personal worth rose from almost one billion dollars in 1999 to USD $2.2 billion. In 2000 he was ranked 121 on the Forbes 400 Richest Americans.