(Adds details on derivative gains)
MEXICO CITY, July 20 (Reuters) - Mexican retail and banking company Grupo Elektra on Thursday reported a net profit of 7.1 billion pesos ($393.4 million) in the second quarter, boosted by higher sales, an improved loan portfolio and a big payoff from derivative bets.
In the same quarter a year ago, Elektra had recorded a net loss of 79 million pesos.
Elektra also said revenue rose 17 percent in the April-June period, to 22.8 billion pesos.
Elektra saw net financial income of 6.87 billion pesos in the second quarter, compared to last year when its costs totaled 3.13 billion pesos.
The company noted in its statement that profits in the first half of this year came mostly from derivatives bets. Among derivative positions, Elektra has a bet on its own stock price.
Elektra's stock price is up over 200 percent this year, and it soared 72 percent in the second quarter.
Elektra, which runs appliance stores that have banking and money transfer businesses, said its EBITDA rose 25 percent.
Elektra, owned by Mexican billionaire Ricardo Salinas, said its loan portfolio grew by 24 percent to 85.1 billion pesos.
Earlier this year, members of Mexico's association of brokerages asked the stock exchange to look into Elektra's share price gains. The company has said it was not aware of what was driving them.
Elektra shares were up 0.57 percent at 819.82 pesos apiece before it reported earnings.
$1 = 18.143 pesos on June 30 Reporting by Gabriel Stargardter and Michael O'Boyle, editing by G Crosse