A benchmark ESG stock index has removed Tesla Inc., sparking a debate about which companies do — and don't — pass muster with socially aware investors.

Tesla has grown into a $735 billion company on the back of its breakthrough electric-vehicle engineering. Its own carbon footprint is a small fraction of its peers, and its success in the market has pushed the industry overall away from gas-powered vehicles.

But the other components of ESG — the social and governance risks — give investors pause. Chief Executive Officer Elon Musk is an unconventional manager, prone to impulsive tweeting, and the company discloses very little information about its workforce or labor conditions.

That split became material Wednesday after it emerged that Tesla was expelled from the ESG version of the S&P 500 Index. Musk responded by saying ESG is "a scam." It added to an already bad day for the company, whose stock fell 6.8% amid a broad sell-off in tech shares.

"This all speaks to the big inconvenient fact about ESG: You can't keep the baby and throw out the bathwater," said Eric Balchunas, senior ETF analyst at Bloomberg Intelligence. "You have to accept or reject both."

In a report, analysts at Bloomberg Intelligence wrote that Tesla's ESG status remains among the most debated for any company, with many ESG-labeled funds still holding the stock. In fact, the world's largest ESG-focused exchange-traded fund has about 1.8% of its assets invested in Tesla, according to data compiled by Bloomberg.

The fund, BlackRock Inc.'s $21.9 billion iShares ESG Aware MSCI USA ETF (ticker ESGU), tracks the MSCI USA Extended ESG Focus Index, which still includes Tesla as a member.

Balchunas and BI's Shaheen Contractor wrote Wednesday that eight of the 15 largest U.S. funds that include ESG in their portfolio filters have significant positions in Tesla.

"Though Tesla might fit an environmental focus or impact theme, the company's social and governance issues make its inclusion in ESG funds debatable and Tesla's removal from the S&P 500 ESG Index perhaps overdue," the analysts said in their posting entitled "Is Tesla ESG?"

S&P Dow Jones Indices, which removed Tesla from its S&P 500 ESG Index, said the company's score on environmental, social and governance standards has remained "fairly stable" over the past year, but it has slipped down the ranks against improving global peers.

The index provider cited concerns related to working conditions and Tesla's handling of an investigation into deaths and injuries linked to its driver-assistance systems. A lack of low-carbon strategy and codes of business conduct also counted against Musk's company, it said.

"While Tesla may be playing its part in taking fuel-powered cars off the road, it has fallen behind its peers when examined through a wider ESG lens," Margaret Dorn, senior director and head of ESG indexes for S&P Dow Jones in North America, said in a Tuesday blog post.

For months now, Tesla has been critical of ESG. The company said in its annual report that ESG ratings are "fundamentally flawed," and in an April tweet, Musk said "corporate ESG is the devil incarnate."

From a market standpoint, Tesla's removal from the S&P index probably will be minimal as there was only about $11.7 billion that tracked S&P ESG gauges as recently as the end of 2020. By contrast, trillions of dollars track the main S&P 500 gauge.

Investors are split on S&P's decision. Kristin Hull, founder of Nia Impact Capital, a sustainability fund in Oakland, California, that has been pressing Tesla to address worker issues, said she was relieved that there was "finally accountability."

Zach Stein, chief investment officer of Carbon Collective, a climate-change focused online investment adviser based in Berkeley, California, said the opposite. The biggest issue in ESG is climate change, so kicking out the leading maker of electric vehicles makes no sense, especially since companies like Exxon Mobil Corp. remain in the S&P index, he said.

Tim Quinson reports for Bloomberg News.

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