Despite fears that the Trump rally is showing signs of weakness, the S&P 500 has risen 1.6 percent in six days of trading, giving the index one of its strongest annual starts in a decade.

The S&P 500 saw its first day in the red on Monday, causing the SPDR S&P 500 ETF Trust (SPY) to fall 0.2 percent by the end of trading. Volumes were weak for the session, falling from 71.6 million shares on Jan. 6 to 46.9 million shares on Jan. 9, the quietest trading day since Dec. 29.

While some analysts worried that the decline was the beginning of a reversal of recent bullish strength, Tuesday morning saw shares reverse an opening decline to rise 0.3 percent by lunch time.

Part of the strength is due to macroeconomic optimism and hopes of broader global demand for goods and services. Clues of robust demand came late Monday from China, where the producer price index rose 5.5 percent year over year in December, far above the 3.3 percent increase seen in November. According to Bloomberg, analyst expectations of 4.6 percent were far short of the mark, which may indicate “the world’s second-largest economy is poised to export inflation around the globe through its supply chains.”

Higher global inflation could indicate broader tolerance for higher prices, which could increase global growth, raise net earnings for firms and drive stock prices higher.

SPY remains slightly shy of its 52-week high price of 228.34, but the S&P 500’s estimated P/E ratio of 26.2 would be the index’s highest since the 2007/2008 Global Financial Crisis. In addition to higher prices, the S&P 500’s earnings contracted for six quarters before seeing meager growth in the third quarter. FactSet believes the index’s earnings will grow 3% year over year in the fourth quarter of 2016.

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