The S&P 500 has just fallen into negative territory after spending most of the day up nicely.
Meanwhile, U.S. Treasuries are quickly regaining much of the ground lost earlier this morning, when risk sentiment was more in vogue.
Some of the jitters may be on account of reports that Russia has sent troops into Ukraine's Crimea region, but it appears that weakness was seeping into markets prior to those reports hitting the tape.
The charts below show the price action in various markets. Across the top from left to right are the S&P 500, the U.S. dollar-Japanese yen exchange rate, and the euro-U.S. dollar exchange rate. Across the bottom are gold futures, 10-year U.S. Treasury futures, and December 2016 eurodollar futures.
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