Complex sentence: His massive financial leverage and the harsh business environment experienced during the Swedish financial crises in 1990-1994 forced Penser to cease control over his holdings, which were sold to Nordbanken, which later became Nordea, for the symbolic sum of 1 SEK each.
Split into simpler sentences: His massive financial leverage and the harsh business environment experienced during the Swedish financial crises in 1990-1994 forced Penser to give up control over his holdings. They were sold to Nordbanken, which later became Nordea, for the symbolic sum of 1 SEK each.