Buzz Stocks: Walgreens Boots Alliance Inc, Tesla Motors Inc, and Rigel Pharmaceuticals, Inc.

U.S. stocks are lower, following the European Central Bank's (ECB) decision to keep interest rates unchanged. Among equities in focus today are pharmacy chain Walgreens Boots Alliance Inc (NASDAQ:WBA), electric auto maker Tesla Motors Inc (NASDAQ:TSLA), and biotech stock Rigel Pharmaceuticals, Inc. (NASDAQ:RIGL). Here's a quick look at what's driving WBA, TSLA, and RIGL today.

• WBA is trading up 3.7% at $80.05, after reporting an earnings win. In addition, WBA announced that the deadline for its $9.4 billion merger with fellow pharmacy chain Rite Aid Corporation (NYSE:RAD) had been extended to early 2017, given the regulatory obstacles that have recently cropped up. Year-over-year, Walgreens Boots Alliance Inc is down over 9%, with recent rally attempts rejected at the shares' 60-week moving average. A fair number of options bettors are likely cheering today's earnings win, with WBA's 10-day call/put volume ratio at the International Securities Exchange (ISE), Chicago Board Options Exchange (CBOE), and NASDAQ OMX PHLX (PHLX) of 2.02 sitting higher than 81% of all other readings from the past 12 months.
  
  
• TSLA is down 2.8% at $197.77, after CEO Elon Musk announced that all new TSLA vehicles will come equipped with the necessary technology to function completely autonomously, with Tesla Motors Inc hoping to roll out this technology as soon as late 2017. TSLA shares are down over 17.5% so far in 2016, and have given up over 26% since notching an annual high in early April. It looks like there's a number of TSLA short sellers who will be celebrating today's drop, with short interest up 5.7% over the last two reporting periods. Shorted shares now account for 23.7% of TSLA's float, an amount that would take over two weeks of trading to cover, at TSLA's average daily volume.
  
  
• RIGL is plummeting this morning, trading down 37.3% at $2.01, after revealing its bleeding disorder drug, fostamatinib, failed a late-stage study. After touching an annual low of $1.88 in March, RIGL managed to more-than-double to notch an 18-month high of $4.38 earlier this month, but today has surrendered nearly all of those gains. Some short sellers are definitely celebrating after this news, though Rigel Pharmaceuticals, Inc. shares are on the short-sale restricted list today. RIGL's short interest soared a whopping 113.2% over the last two reporting periods, now accounting for almost 6% of RIGL's float, which would take just under a week of trading to cover, at the stock's average daily volume.

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