Traders originally attributed the central bank's aggressive midpoint settings to a visit by US Secretary of State John Kerry, but Kerry has since left China and yet the People's Bank of China continues to signal permission for the market to scale fresh heights.
Ordinarily the central bank sets the midpoint inversely to overnight moves in the dollar index to keep the rate stable, but the midpoint rose on Tuesday even though the dollar index also climbed overnight.
The move also flies in the face of predictions that Beijing would devalue the yuan alongside the Japanese yen after the Japanese government embarked on an economic stimulus programme that saw the yen lose nearly a quarter of its value against the dollar in the past six months.
Some traders theorized that the strong midpoint settings are intended as a gesture at recent pessimistic moves by foreign ratings agencies questioning China's management of its local debt.
Intraday volatility in the yuan spot market is controlled by the central bank's daily midpoint setting. The exchange rate is only allowed to diverge from the midpoint by 1 percent in either direction, making the midpoint setting in the morning the signal of how much appreciation or depreciation regulators are willing to permit. In the past the bank has used the midpoint to leash the market when it felt that corporates were being too optimistic or pessimistic about the future value of the yuan.
In recent weeks, however, the central bank has repeatedly set the midpoint at record highs against the dollar, which has allowed the spot market to take advantage of the new range to set new records as well.