This article originally appeared on Real Money, our premium site for active traders, at 12:30 p.m. ET today. To get great columns like this from Jim Cramer and other top columnists earlier in the trading day, click here.

The heat is on Kroger (KR) - Get Kroger Co. (KR) Report .

The supermarket giant cut its full-year earnings guidance to between $2 and $2.05 a share from its previous view of $2.21 to $2.25 a share. Wall Street was around $2.20 a share in its estimates. Shares crashed as much as 17%. The company pinned the blame on rampant food-price deflation, which probably means ugly quarters will be revealed by General Mills (GIS) - Get General Mills, Inc. (GIS) Report , Kellogg (K) - Get Kellogg Company (K) Report and other packaged-food players in July.

But finding the source for Kroger's deflation problem isn't too hard. As TheStreet wrote on Wednesday, Walmart is back, baby. The company is slashing prices across the board in attempt to turn up the heat on Kroger, Aldi, Target (TGT) - Get Target Corporation Report and everyone else known to man.

I can tell you that Walmart is not the same company it was five years ago (or even a year ago). It's hungry, determined and moving at a speed that should frighten a grocery store like Kroger and fellow discounter Target. As Walmart's renewed winning ways feed through to the staff, it will likely fuel stronger results and more headaches for rivals.

Game on. 

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Beware Tesla fanboys: Tesla  (TSLA) - Get Tesla Inc Report is burning money, but shareholders are the likely ones to blister and feel the pain. The standard 90-day corporate equity lockup period for Tesla, following its $402.5 million stock sale of March 16, ends Thursday, TheStreet reports. As a result, Tesla will be free to conduct another stock offering as soon as Thursday, which is a real possibility given the electric car company's debt situation, partly due to its Solar City investment, and need for additional cash. Any new issuance the company may seek would likely need to take place before July, which is when Tesla issues its quarterly report on car sales. Alternatively, an offering could come in late August after Tesla issues its quarterly financial report.

Shares could start to come under pressure. 

Mining stocks get whipped: Global mining stocks found themselves in a hole Thursday, TheStreet reports, after South Africa's government said at least 30% of domestic mining assets should be black-owned even if previous black owners sell their stakes. South African-exposed mining companies fell sharply in the wake of the announcement. London-listed Anglo American PLC (AAUKF) tumbled 4.4% to 1,013 pence ($23.87) a share, South32 Ltd. fell 4% to 158 pence, BHP Billiton PLC (BHP) - Get BHP Group Ltd Sponsored ADR Report was down 2% to 1,155 pence, Rio Tinto (RIO) - Get Rio Tinto plc Sponsored ADR Report fell 2% to 3,079 pence and Glencore PLC (GLNCY) fell 2.6% to 279.2 pence. South African gold producers were hit even harder. Sibanye Gold Ltd. (SBGLF) plummeted 6.7% to 1,562 South African rand ($121.38) and AngloGold Ashanti Ltd. (AU) - Get AngloGold Ashanti Limited Sponsored ADR Report fell 4.8% to 14,015 rand.

Amazon eyes a new prize: Amazon  (AMZN) - Get, Inc. Report may be preparing a deal to buy Slack Technologies in a deal that could value the messaging startup group at more than $9 billion, TheStreet points out. With Microsoft's (MSFT) - Get Microsoft Corporation (MSFT) Report deal for LinkedIn being well-received, this deal seems logical for an Amazon that is aggressively expanding into the cloud.

One has to wonder, though: Why isn't Apple (AAPL) - Get Apple Inc. (AAPL) Report considering Slack, or for that matter, Twitter (TWTR) - Get Twitter, Inc. Report ? Each service would provide valuable insight into human behavior, which could be used in building new products and services. 

Apple is a holding in Jim Cramer'sAction Alerts PLUS Charitable Trust Portfolio. Want to be alerted before Cramer buys or sells AAPL? Learn more now.

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