Smart & Final Stores Inc. announced Tuesday afternoon that it has agreed to be acquired by private-equity firm Apollo Global Management LLC for $6.50 a share in cash. Smart & Final stock closed Tuesday at $5.39 a share, and popped more than 18% higher in after-hours trading to reflect the agreement. At $6.50 a share, Smart & Final would have a market cap of about $500 million. Apollo previously bought Smart & Final for $22 a share in 2007, then sold it to Ares Management in 2012; the company went public in 2014, but was still majority-owned by Ares.