The PBOC's foreign currency desk, run under Deputy Governor Xuan Changneng's mandate, has held the daily yuan reference rate inside a 40-pip band since September 11, the longest stretch of fixing stability this quarter, according to the daily fixings the desk publishes each morning at 9:15 Beijing time. That stillness is a decision, or more precisely, it is the absence of the one decision the desk has made routinely all year: nudging the fixing to absorb pressure before a data release or a diplomatic date. The desk is choosing not to signal ahead of the September 24 Trump-Xi meeting, which China had threatened to cancel over the $14 billion Taiwan arms sale disclosed September 13, a threat that Washington's now-reported delay of that sale's timing was built to defuse.

A fixing desk that stays quiet before a summit is not undecided, it is waiting for Washington's arms-delivery calendar to move first, because the yuan's stability currently rests on an assumption about a schedule the PBOC does not control. Mainland credit desks price offshore yuan forwards off the fixing's implied volatility, and eight sessions of near-zero movement have compressed one-month CNH implied vol to its narrowest range since June, a bet that the summit produces no surprise big enough to require a fixing response. The PBOC's foreign currency desk has until the next fixing window after September 24 to show whether that bet was right.