Oil-tanker rates on the industry’s benchmark trade route snapped the biggest advance this year amid speculation demand slowed for cargoes to load this month.

Costs for very large crude carriers on the Saudi Arabia-to-Japan route slumped 3.4 percent to 45.06 Worldscale points today, according to the Baltic Exchange in London. Freight costs for the 2 million-barrel cargoes jumped 19 percent last week, the largest such gain since at least the start of the year.

“Volumes are expected to quiet down this week as much of the crude-cargo loading program for June has been concluded,” Omar Nokta, a New York-based analyst at Global Hunter Securities LLC, said in an e-mailed note today. Rates may “drift” until traders seek the ships they need for July loadings, he said.

Oil companies arranged charters equating to almost 40 percent of an average month in two days last week, Marex Spectron Pte, a Singapore-based freight-swaps broker, said in a report May 31. There are about 58 vessels competing for 17 cargoes this month, it said in a separate note today.

The current Worldscale rate on the benchmark route equates to daily earnings of $21,426 for VLCCs, down 10 percent from the prior session, the exchange’s figures showed.

The largest one-day change in prices for crude tankers was the Saudi Arabia-to-Singapore VLCC route, where costs slid 4 percent to 45.78 Worldscale points. Prices for delivering European gasoline to the U.S. East Coast fell 1.1 percent to 129.32 Worldscale points, the biggest movement in rates for refined-fuel tankers.

Worldscale points are a percentage of a nominal rate for more than 320,000 specific routes. Flat rates for every voyage, quoted in dollars a ton, are revised annually by the Worldscale Association in London to reflect changing fuel costs, port tariffs and exchange rates.