(Adds details of results, background, analyst note, share reaction)
SAO PAULO/BRASILIA, July 13 (Reuters) - Brazil's GPA reported strong quarterly revenue growth on Friday, as robust sales in its wholesale stores offset the negative impact of a major truckers' strike, sending shares up almost 5 percent in midday trading.
The company, owned by France's Casino Guichard Perrachon SA , said revenue climbed 10.4 percent from a year ago in the second quarter to 11.775 billion reais ($3 billion), driven by growth in its wholesale Assai stores. The figure was just below the mean estimate of analysts polled by Reuters for 12.2 billion reais.
Investors cheered the news, sending up GPA shares by 4.7 percent in midday trading in Sao Paulo, their biggest intraday gain since February. Brazil's benchmark Bovespa index was up about 0.6 percent.
Same-store sales, a gauge of sales at stores open for at least 12 months, grew 5.4 percent in the quarter through June.
The performance shows how loyalty programs and other incentives, a shakeup in store formats, and improved consumer confidence continue to carry the food retailer despite macroeconomic headwinds in Brazil.
It also indicates that GPA's results are on track following a management shakeup that took effect in April.
A nationwide protest by truckers in May, which rattled Latin America's largest economy, had a negative impact on total revenue of 0.7 percent, with the Assai division harder hit than more traditional formats, the company said.
Still, same-store sales at the Assai wholesale division climbed 4.7 percent, while sales at the company's more traditional Multivarejo stores climbed 5.8 percent.
GPA opened 20 new Assai stores over the past year, amid the growing popularity in Brazil of big box stores making high-volume sales to smaller retailers and thrifty consumers.
Within the Multivarejo division, the company's flagship Pao de Acucar brand was the top performer, with same store sales climbing some 7.9 percent.
The company attributed growth in the Multivarejo division in part to the continued rollout of loyalty programs and efforts to boost online sales since GPA shook up management.
In a note to clients, Sao Paulo brokerage Coinvalores called the results "positive," pointing in particular to market share gains for some of the firm's Multivarejo formats.
Holidays and one-time events also had some effect, including a boost in shopping ahead of the soccer World Cup tournament and an earlier Easter that moved much of the shopping for that holiday into the first quarter of 2018.
Shares in parent company Casino were up 0.8 percent.
$1 = 3.88 reais Reporting by Gram Slattery in Sao Paulo and Bruno Federowski in Brasilia; Additional reporting by Flavia Bohone in Sao Paulo; Editing by Bernadette Baum