Shares of Uber (UBER) downshifted again on Tuesday, dropping to their lowest level since the company's initial public offering in May, as investors continued to re-visit the company's revenue and growth prospects following its latest quarterly results.

Shares of the ride-sharing and delivery technology company were down 1.24% at $36.53 in early trading on Tuesday after dropping 7.6% on Monday to $37, below its previous low of $37.10 on May 13. They had recovered somewhat by late morning, settling at $36.98.

Since its May IPO at $45 a share, Uber shares have shed roughly 18% of their value.

Uber's stock took a sharp U-turn last week after the company posted a $5.2 billion quarterly loss, driven primarily by stock-based compensation costs. The company reported a per-share loss of $4.72 on revenue of $3.17 billion, both of which missed analysts' estimates.

Investors continue to remain skeptical about whether or not Uber can achieve profitability in the future. Those concerns have put Uber and rival ride-hailing company Lyft (LYFT) under pressure in the months since their respective IPOs. Shares of Lyft fell 4.9% on Monday to $56.18. They began the trading day Tuesday down another 1.74%, though reversed course by late morning, gaining a little over 1% to $56.80. 

Uber users, meantime, continue to revolt against the company's perceived lack of standards in conducting background checks on its drivers, and in its technology, which makes it difficult if not impossible to question charges.

Dear @Uber, I do not understand how my daughter, after celebrating her birthday in Liverpool, gets quoted "£47-£55" for a 6 seater car to return to Heswall (about 10 miles) and ends up being charged £86.60! Nearly double the quote and £9 a mile !!! #Uber @Uber_Support.

— Stephen Forster (@sdforster99) August 11, 2019

"While you often have to make trade-offs in life, we believe that we can continue to invest aggressively and grow while driving efficiencies from scale by building great tech to improve effectiveness and from good old-fashioned focus on the bottom line," CEO Dara Khosrowshahi told investors on a post-earnings conference call.

"I think you know that the balance between the top and the bottom line is more of an art rather than a science. So I if I told you that we had kind of the scientific formulae that we're solving for here, we'd be lying to you."