Last week, the rupiah's value against the US dollar took a ride on a roller coaster. It nose-dived to 11,500 before going up to Rp10,000. Were it not for support from Bank Indonesia (BI) and state-owned enterprises (BUMNs), it would have crashed to 12,000 to the greenback. All through last week, the institutions showered the market with dollars. "The amount shot up from around $20 million to $50-$80 million," said a foreign bank dealer in Jakart