Lemonade shares fell Wednesday after the digital insurer reported strong second-quarter revenue growth, but rising expenses overshadowed the results.

Shares were recently down about 24% at $47.43.

Lemonade said its second-quarter loss narrowed to $43.4 million, or 56 cents a share, from a loss of $43.9 million, or 60 cents a share, a year earlier.

Revenue rose 79% to $294.4 million from $164.1 million a year earlier, compared with analysts expectations of $291 million.

Lemonade said in-force premium, a key measure of future revenue potential, reached $1.43 billion at the end of June, up 32% from $1.08 billion a year earlier. Customers grew to 3.31 million from 2.69 million last year.

However, expenses weighed on the quarter. Executives said on the earnings call that general and administrative expenses rose 85%, partly because the year-earlier period benefited from a one-time tax refund. Marketing expenses increased 30%, while other insurance expenses rose 25%.

On the call, executives highlighted the company's artificial intelligence capabilities and recent launch of a Tesla-focused auto insurance offering as areas where Lemonade believes it has an advantage over traditional insurers.

Lemonade said customers using Tesla's Full Self-Driving technology in states where the offering is available can receive a 50% reduction in premiums for miles driven under autonomous control.

"That's a pretty dramatic saving," said Chief Executive Daniel Schreiber, adding that Lemonade's ability to price policies on a per-mile and per-driver basis gives it an advantage over insurers relying on traditional underwriting factors.

The product demonstrates Lemonade's broader push toward "micro pricing" rather than relying on broad customer categories. Traditional insurers, Schreiber said, have less incentive to adopt telematics because more precise pricing could reveal that some customers are overpaying while forcing others to pay more.

Executives also highlighted growth in pet and auto insurance. Pet insurance has reached about $500 million in premium, while renters insurance continues to serve as a key source of customers for cross-selling.

The company said about half of its auto policies are currently sold to existing customers, reducing customer acquisition costs compared with insurers that rely primarily on acquiring new auto customers.

Executives said Lemonade's ability to bundle products across renters, pet, home and auto insurance could become a long-term advantage.

Lemonade said it continues to expand internationally, with Europe seeing triple-digit growth for several years. Executives said newer markets, including the U.K., have benefited from lessons learned from earlier launches.