Key Takeaways Treasury yields spiked on Wednesday after a Treasury debt auction suggested concerns about unsustainable government deficits are eroding demand for federal debt.Morgan Stanley analysts in a note earlier this month forecast yields at their current level would spill over into the stock market and pressure valuations. Credit rating agency Moody's on Friday downgraded U.S. government debt as Congress crafted a tax and spending bill that's expected to add trillions to America's public d...