The latest update on the grocery wars is here, with Walmart and Costco gaining ground

• Value-focused retailers are picking up market share and traditional chains are sliding.
• Households are hunting for grocery deals to offset rising costs of other bills.
• Fuel pressures may drive more inflation, but Walmart and Costco are typically slow to raise prices.

The grocery wars continue to heat up.

As US households continue to grapple with rising costs for gas, housing, and insurance, they're increasingly looking for savings on groceries.

That's giving value-focused retailers like Walmart and Costco a major leg up over more traditional grocery giants like Kroger and Albertsons.

Data released this week from consumer analytics firm Numerator showed warehouse giant Costco overtook Kroger's dollar share of US retail food and beverage sales. Costco has steadily gained share over the last two years as both Kroger and Albertsons shrank their positions.

The estimates are based on the last 12 months of sales, and show Costco's share ticking up to 8.4%, a half percentage point higher than the same period a year earlier.

And even though Walmart has long held the largest share of grocery spending, it managed to gain 0.2 percentage points to capture 20.3% of sales in the period.

By comparison, Kroger's share fell by 0.2 percentage points to 8.2% while Albertsons saw its share slide by 0.1 percentage points to 4.5%.

The shifting grocery landscape comes at a time when US shoppers are facing fresh inflation increases from last year's trade war and this year's conflict with Iran.

Costco has also managed to keep prices steady this year, but the wholesale club's leaders say they are closely watching the latest cost pressures.

Groceries haven't been significantly affected by rising diesel and transportation costs just yet, but a recent note from Deutsche Bank said Walmart is bracing for an impact that would outweigh the benefit the company received in tariff refunds this year. Walmart initially planned to invest some of those refunds in price cuts.

Deutsche Bank also said that when Walmart raises prices, its competitors do too, and Walmart typically remains the lower-priced option.

Traditional grocers aren't sitting quietly as Walmart and Costco pull ahead, though.

Kroger has been taking a page — and a CEO — from Walmart's book this year, adding Greg Foran, who formerly led Walmart's US business.

Foran's big focus this year is on lowering prices for consumers and tightening operations to make that happen. It's a $5 billion effort that includes significant cuts to the corporate workforce over the next few years and ending contracts with suppliers that aren't delivering a good enough deal.

And Albertsons said it is making several significant adjustments to its employee benefits package to manage its business in the face of rising healthcare costs.

Whether it's Walmart and Costco or Kroger and Albertsons it increasingly looks like the path to gain share in this market includes a sharper focus on value.