The People's Bank of China (PBOC) set the yuan midpoint slightly weaker for the second consecutive day on Tuesday at 6.3411 to the dollar.
The central bank's move partly reflected a slight firming of the dollar index in overnight trade, which measures the greenback against a euro-dominated basket of currencies.
But spot yuan rates showed no reaction, moving a mere 5 pips from open to 6.3575 at midday in thin trade, after closing at 6.3568 Friday.
Lack of hard information on upcoming moves by central banks in the United States, Europe and China kept customers from making strong bets in either direction, traders said.
So far this year the yuan has depreciated just 1 percent against the dollar, having strengthened by around 23 percent against the dollar since the landmark revaluation in 2005.
MORE DEPRECIATION TO COME
Investors appear to be increasingly betting on further depreciation over the next 12 months.
Offshore 1-year non-deliverable forwards NDFs have been suggesting yuan depreciation since March, although differing interest rates in Hong Kong and the mainland play a role in the gap.
However, the spread between the NDF and the spot rate has continued to widen steadily. On Tuesday, NDFs changed hands at 6.4508, around 1.4 percent weaker than the spot price.
Onshore 1-year yuan forwards took longer to change directions. Once a consistent predictor of yuan appreciation expectations in the onshore market, they swung toward predicting depreciation in July and are now trading close to the NDF price at 6.4820 per dollar.
Traders expect the spot yuan to move between 6.35 and 6.37 against the dollar in the near term.
In trade-weighted terms that account for inflation, the yuan's real effective exchange rate index (REER) is still up as of July from the end of 2011 at 100.69 (from a base of 100 as of December 2011), per Reuters calculations.
The offshore yuan in Hong Kong continues to trade slightly weaker than its onshore cousin, at 6.3577 per dollar at midday.