UPDATE: Insurer James River shares slide 22% after it cancels policies issued to Uber's commercial auto business

Shares of insurer James River Group Holdings Ltd. /zigman2/quotes/202205552/composite JRVR -1.22% slid 22% Wednesday, after the insurer said it plans to cancel all policies issued to its biggest customer, Uber's /zigman2/quotes/211348248/composite UBER +1.81% commercial auto business Raiser LLC. "This account has not met our expectations for profitability, and we think it best to terminate the underwriting relationship as of year end," Chief Executive J. Adam Abram said in a late Tuesday statement. The account accounts for about $20% of the company's trailing 12-months premiums and about 35% of trailing 12-month premiums in the e&s (excess and surplus) segment, according to B. Riley analyst Randy Binner. Binner downgraded the stock to sell from neutral on the news and said concerns about reserve adequacy will likely weigh. "While we do not have full 3Q19 financials, the expected top-line decrease from the fall off of the Uber book, margin compression from reduced scale, and increased conservatism on reserve adequacy has moved 2019E EPS from $2.60 to $1.00, and 2020E EPS from $2.65 to $2.25," the analyst wrote in a note to clients. James River shares are up 4% in 2019, while the S&P 500 /zigman2/quotes/210599714/realtime SPX +0.11% has gained 15%. Uber shares were up 0.9% premarket but are down 34$ in the last three months.