It's a more tepid start to the day as European stocks are opening a touch lower, although the declines are relatively modest for the most part. Investors are keeping a more cautious mood ahead of the Fed decision and big tech earnings later in the day. Here are the opening changes:Eurostoxx -0.1%Germany DAX -0.1%France CAC 40 -0.1%UK FTSE -0.3%Spain IBEX -1.1%Italy FTSE MIB -0.2%Spanish stocks are the notable laggard in early trading, with the IBEX falling by more than 1% as Banco Santander shares come under pressure again. Elsewhere, the declines are relatively contained as European investors appear reluctant to take on much risk ahead of the major events still to come.The Fed decision is the obvious event that jumps out on the calendar, though the central bank is widely expected to leave interest rates unchanged later today. The bigger question will be what policymakers signal about December instead. And with bond yields still elevated and inflation concerns lingering, any hawkish surprises could easily unsettle the broader risk mood.Then, we have Microsoft and Alphabet reporting earnings after the US market close. Both will be closely watched for clues on the AI trade, particularly whether strong growth in cloud and AI businesses can continue to justify the massive spending commitments.As for European markets, the focus will slowly shift towards the ECB decision tomorrow. That being said, the central bank is expected to stand pat for now but investors will have to be mindful about developments in the bond market - especially with questions surrounding the December policy outlook still unresolved.For now, it is shaping up to be a rather tentative start to the session. However, there will be plenty of potential catalysts to shake things up and investors will more than likely have to keep their powder dry until we get some clearer answers. This article was written by Justin Low at investinglive.com.