Goldman Sachs thinks Walmart Stores Inc.  (WMT - Get Report) has run too hot.

After the retail giant blew away Wall Street's expectations for its third-quarter last week, Walmart's stock soared over 10%.

But now analysts at Goldman Sachs contend that this year's impressive ramp up (shares are higher nearly 40% year-to-date) appears to be cooling.

The firm cut Walmart's stock to "Neutral" from "Buy" while assigning it a $100 price target because of its current valuation. Shares of the retailer were falling over 1.2% during mid-morning trading on Monday following the downgrade.

Goldman's downgrade is predicated on Walmart's "progress in growing earnings while investing in its business has been recognized by the market, as the stock's multiple has surged," Goldman analyst Matthew Fassler wrote in a note obtained by CNBC.

Presently, Walmart's forward price-to-earnings multiple is 21 times, or a 15% valuation premium versus the S&P 500, Fassler explained. "From here, though, the stock looks fairly valued. Benchmarked vs. global peers, even on our new, higher numbers, the stock does not offer value for its underlying growth."

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