Before the market opened, the People's Bank of China (PBOC) set the yuan's midpoint at 6.3028 to the dollar, the highest fixing since late June. The midpoint has climbed steadily since markets reopened after a holiday week in the first week of October.
Spot yuan opened at 6.2550 against the dollar, stronger than Tuesday's record closing high of 6.2640, continuing an upward trend that began late September.
Market participants have been struggling to explain why Chinese central bank has pushed the midpoint upwards, and some speculate that Beijing is trying to provide US President Obama with rhetorical firepower against Republican candidate Mitt Romney, who criticised him for refusing to formally label China a currency manipulator.
"As far as currency manipulation, the currency's actually gone up 11 percent since I've been president because we have pushed them hard," Obama said, during the second presidential debate, which occurred as China's forex market opened on Wednesday.
"It is increasingly clear that geopolitics may be triggering the rally in the CNY," wrote Dariusz Kowalczyk, forex strategist at Credit Agricole CIB and leading advocate of the thesis that Beijing is meddling with the yuan for diplomatic purposes.
"Beijing may have modified its FX policy to respond to US pressure," he wrote in a research note distributed Wednesday.
Traders, however, say the third round of US monetary loosening has put downward pressure on the dollar index, and by extension propped up the yuan.
The dollar index has been sliding steadily this week, and a trader at a Chinese bank in Shanghai said this has continued to encourage investors to go long on the yuan.
"Even though there is some dollar buying activity, while the dollar trend remains weak, the yuan's exchange rate will continue to climb," he said.
However, traders told Reuters that the yuan is encountering resistance at 6.25 against the dollar, at which point corporates, in particular firms which trade in natural resources, move in to buy dollars.
A Reuters poll of 20 FX analysts earlier this month showed that on average, they expect the yuan to gain an additional 0.9 percent over the next 12 months to 6.23.
But analysts also expect a pull-back in the near term.
The consensus forecast is that the yuan will end 2012 at around 6.30, slightly below the 6.2940 level where it closed 2011.
In trade-weighted terms, the yuan's relative value against a basket of currencies has been slipping steadily since mid-summer.
According to data from the Bank of International Settlements released Monday, the yuan's trade-weighted value in nominal terms fell by 1.4 percent over July through September, and it also began declining in real terms in August.
Offshore non-deliverable one-year forwards (NDFs) continue to imply depreciation, although they have begun to firm alongside spot prices. NDFs changed hands at 6.3510 at midday.