(Bloomberg) -- Online car retailer Carvana Co. reported a sixfold increase in net income and record quarterly sales of used vehicles, countering some of the bear arguments put forth recently by short sellers.

Most Read from Bloomberg

• The World’s Data Center Capital Has Residents Surrounded

• An Abandoned Art-Deco Landmark in Buffalo Awaits Revival

• Budapest’s Most Historic Site Gets a Controversial Rebuild

• San Francisco in Talks With Vanderbilt for Downtown Campus

• We Should All Be Biking Along the Beach

Carvana’s sales growth helped push earnings per share to $1.28, surpassing the average estimate of analysts surveyed by Bloomberg. Revenue rose 42% from a year earlier and also beat estimates.

The shares jumped as much as 17% in extended New York trading.

Famed short seller Jim Chanos publicly shorted the stock earlier this year, saying its profits are primarily driven by the sale of loans it originates — not from selling cars — and that it’s overvalued after a long run up in the shares. The stock has risen more than 160% over the past 12 months.

In most quarters Carvana gets most or all of its income from selling car loans that it originates, or would have lost money without those gains. The company books the entire value of the loan sale at once, while other retailers book the revenue over the life of the loans.

In the second quarter, Carvana said loan sales accounted for $274 million of its $308 million in profit.

Still, Carvana Chief Executive Officer Ernest Garcia III has been growing the company’s sales and says that, with just 1.5% market share in the US used-car market, there is more room to run. The company added inventory in the quarter and made more available to potential buyers.

Carvana also plans to boost its advertising spending with a brand-building campaign in the current quarter.

“We’re on plan,” Garcia said on an analyst call. “We grew sales by 41% year-over-year. We grew inventory available for our customers by 50%. So we’re obviously growing production a little faster than we’re growing sales.”

Garcia also has been wringing costs out of the company’s sales and vehicle reconditioning networks. Operating expense per retail unit sold shrank by about $150 from a year ago.

Carvana maintained its full-year outlook for earnings before interest, taxes, depreciation and amortization in the range of $2 billion and $2.2 billion, roughly bracketing the average analyst estimate.

The company also disclosed in a regulatory filing that it received a subpoena in June from the Securities and Exchange Commission related to allegations made in a short-seller report in January. Hindenburg Research, which has since been disbanded, issued a report that month alleging that the company had lax underwriting standards and sold its subprime loans to related parties to pad its profits. Carvana refuted the allegations.