The mixed open reflects a region caught between a soft Wall Street handover and the looming Fed decision, with little conviction in either direction until the outcome is known. A hawkish surprise from the Fed would likely pressure Asian equities further and support the US dollar against regional currencies, while a more measured outcome could see risk appetite recover quickly given how much caution is already priced in. The surge in US Treasury yields to their highest level since 2007 is the more significant undercurrent here, as it tends to weigh on rate-sensitive and growth-oriented sectors across Asian markets, and could keep pressure on the yen if the gap between US and Japanese yields continues to widen. AUD is likely to stay reactive to the same risk-off cues driving broader Asian sentiment, with little independent domestic catalyst overnight.-- Asia opens without conviction, torn between a soft Wall Street lead and the wait for the Fed's verdict later this week.Summary:Asia-Pacific stocks opened mixed on Wednesday, September 16, following a weak handover from Wall StreetThe Nikkei 225 opened marginally higher, up around 11 points or 0.02%, near 63,495The Kospi opened lower, down around 12 points or 0.17%, near 6,616Wall Street fell on Tuesday, with the Dow down 0.63%, the S&P 500 down 0.45% and the Nasdaq down 0.78%, as the 10-year Treasury yield spiked to its highest level since 2007 above 5%Oil prices rose further on Tuesday, adding to the pressure on US equities ahead of the Federal Reserve's rate decisionAI-related stocks were a bright spot on Wall Street, with Coherent, AMD and Qualcomm all gaining after chip stocks had been under pressure the previous sessionAsia-Pacific stocks opened mixed on Wednesday as the region remained cautious following a weak handover from Wall Street, with investors bracing for the Federal Reserve's interest rate decision later this week.The Nikkei 225 opened little changed, up around 11 points or 0.02%, near 63,495, while the Kospi opened lower, down around 12 points or 0.17%, near 6,616. The divergence points to a region without a clear directional bias, as traders wait for clarity from the Fed before committing to a firmer stance in either direction.The soft start followed a lower close on Wall Street on Tuesday, where the Dow Jones Industrial Average fell 0.63%, the S&P 500 dropped 0.45% and the Nasdaq Composite lost 0.78%. The session was dominated by a sharp rise in the 10-year Treasury yield, which briefly touched its highest level since 2007, above 5%, as rising oil prices added to inflation concerns just a day ahead of the Fed's policy announcement. Despite the broader decline, AI-related names were a relative bright spot, with Coherent, AMD and Qualcomm all posting gains after chip stocks had come under pressure in the prior session.The rise in Treasury yields is likely to remain a key theme for Asian markets in the near term, given its influence on relative currency and equity valuations across the region. A further widening in the yield gap between the US and Japan could add pressure to the yen, while continued strength in oil prices keeps energy costs, and by extension inflation expectations, elevated across import dependent economies in the region.With the Fed's decision due Wednesday in the US, Asian traders are likely to keep positioning light into the announcement, wary of taking on directional risk ahead of an outcome that markets have been pricing as a close call between a hold and a hike. Until that clarity arrives, the region's markets look set to trade within a narrow, headline driven range. This article was written by Eamonn Sheridan at investinglive.com.