Look at this result from blockchain_market_price_history:
{"jsonrpc":2,"id":1,"method":"blockchain_market_price_history","params":["CNY","BTSX","20141017T153600",180000,"each_hour"]}
{"timestamp":"20141019T170000",
"highest_bid" :0.1392757660167131,
"lowest_ask" :0.13793103448275865,
"opening_price":0.13332977787259007,
"closing_price":0.13332977787259007,
"volume":15496560,"recent_average_price":null}
Both opening_price and closing_price are LOWER than the lowest_ask over the given 1 hour period. How is that possible?