Looing back over the past four plus years, Tesla has now delivered a negative return to investors. The latest decline came after Elon Musk's electric vehicle maker revealed second-quarter earnings post -market Wednesday. The stock sank 15% on Thursday in reaction, sending the stock to levels it last traded at within the past year, but crossed for the first time more than four years ago. Shares of Tesla continued to slip on Friday, down another 3%. So with the stock off more than 18% this week, is this an opportunity to buy one of Elon Musk's companies? Wall Street analysts are urging some caution. Results not there "We think they've made some pretty substantial technology investments over the last five or six years around chips and other elements that are going into this shift into physical AI, but the results just aren't there," Oppenheimer analyst Colin Rusch said on CNBC's " Squawk Box " Thursday. "We heard about Optimus being delayed," Tesla's humanoid robot, "FSD (full self-driving) continues to be delayed, and I think what investors are looking for is monetization of these new technologies." Rusch has a neutral rating on Tesla. A majority of Wall Street analysts haven't labeled Tesla as a buy since the first quarter of 2023, when the stock was off about 70% from its recent high in 2021, according to FactSet data. No investment banks upgraded or downgraded Tesla after the latest results, which delivered a revenue beat but an earnings miss as free cash flow turned negative and gross margins narrowed. A few analysts lowered their share price targets, however. Weighing on the Tesla outlook is its pledge to increase capital spending, as the company looks to diversify beyond electric vehicles . Investment drag "Last qtr TSLA's transition from autos to AI became obvious. This qtr, we're starting to see the expenses ... and it may dent profitability for longer than we anticipated," wrote Truist Securities analyst William Stein in a note Wednesday. "We continue to believe these investments will pave the way for TSLA's AI transition, but they will weigh on margins and cash flow for a while." TSLA 5Y mountain Tesla 5-year. Stein maintained a hold rating on Tesla, but lowered his price target by 14%, to $370 from $430. Compared to Thursday's close, that implies a 16% gain. Canaccord Genuity analyst George Gianarikas rates Tesla a buy, but even he acknowledged that the bullish case is getting harder to make. "The Tesla thesis on paper is intoxicating. You have iconic products redefining industries or defining new ones, a founder who appears to be capable of bending markets to his will, and conference call breadcrumbs (in our opinion) that point straight to a blockbuster SpaceX union," Gianarikas wrote Wednesday. "Yet the reality in the ledgers is uncompromising. It is currently a story of stagnant margins, negative free cash flow impacted by long-term investments, and breakthrough promises anchored to timelines hard to measure and model." Merger speculation Canaccord is watching Tesla more closely to see if it can build momentum through its robotaxi business and a potential merger with SpaceX. Analysts who commented on a potential Tesla merger with SpaceX said it remains a tailwind, but no one detailed how the latest financials and attendant declines in both stocks change the exact outlook. While some are worried about the billions in capital investment, others have faith that it will eventually yield strong returns. Cathy Wood's Ark Investment Management added shares of Tesla on Thursday to a several of its ETF funds after the latest stock slide. Piper Sandler analyst Alexander Potter reiterated an overweight rating and $500 price target on Tesla, saying the share price weakness was to be expected and that the company can win investor favor again. "Full self-driving subscriptions continue rising at a much faster-than-expected pace … Record margins in Service are also heartening," Potter wrote. "To break out of its current range, we think TSLA will need to disprove doubts re: Optimus and Cybercab ... We're still believers, but admittedly, catalyst timing is difficult to predict."