Tesla's (TSLA) recent high-profile robotaxi test in Austin, Texas, comes as more negative data emerges in its core auto business, with the company's stock dropping in the process.

Per the European Automobile Manufacturers Association (ACEA), Tesla EV registrations (a proxy for sales) in Europe fell 27.9% to 13,863 in May compared to a year ago. Meanwhile, overall EV registrations in the region, which includes the UK and the European Free Trade Association, rose 25% in May, with overall registrations down 0.6%.

May's total marks the fifth straight month of declining Tesla sales in the European region. May's total was better than the fall seen in April, however, when sales dropped a whopping 49% year over year.

Tesla stock was down over 5% in early trade.

Read more about Tesla's stock moves and today's market action.

The wider availability of the Tesla Model Y may have helped, but sales numbers in May were down compared to April. Tesla sales year to date in Europe through May are down 37.1% to 75,196 units.

Reuters' report of country-specific data was not confidence-building. France's PFA national auto lobby reported new Tesla registrations dropped 67% in May to 721 units, with overall sales down 47% year to date. Mobility Sweden reported Tesla EV registrations tumbled 53.7% to 503 units in the country in May from a year earlier.

Reuters reported Tesla registrations fell 30.5% in Denmark, 36% in the Netherlands, 19% in Spain, and a massive 68% in Portugal. Norway was the only territory in Europe to show sales gains for May.

Demand weakness in the EU came after CEO Elon Musk's foray into Trump administration politics, causing some Tesla owners to become disillusioned with him, specifically by his right-leaning tendencies, support of right-wing leaders in Europe, and leadership of the Department of Government Efficiency (DOGE) in the US.

Musk's recent return to his businesses from politics is seen as a welcome move, per analysts, including Wedbush's Dan Ives, but many wonder if Musk's escapades will permanently damage Tesla's reputation. Musk's recent attacks on President Trump now have both liberals and conservatives upset with the mercurial CEO.

Tesla does not report sales by region or monthly, meaning next week's second quarter production and delivery report will be a big one.

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Last week, Wells Fargo's Colin Langan wrote in a note to investors that Tesla's fundamentals are coming in worse than expected. The bank is expecting second quarter deliveries to be down 21% compared to a year ago, with the firm's 343,000 estimate approximately 17% below the Street consensus of 411,000.