Clean tanker rates for refined petroleum products on top export routes were mostly lower on Wednesday with transatlantic earnings struggling with more vessels available for hire.

Rates for medium-range (MR) tankers for 37,000-tonne cargoes on the TC2 route from Rotterdam to New York were at W134.38, or $11,968 a day when translated into average earnings.

That compared with W135.42 or $12,458 a day on Tuesday and W139.17 or $13,100 a day last Wednesday.

"While there has been a steady flow of cargoes ex States for discharge Continent, rates have come under pressure," broker Fearnleys said on Wednesday, referring to cross transatlantic trade.

"Our outlook for the coming week is still a market with rates under pressure."

Earlier this month, earnings reached their highest since mid February, helped by firmer bookings for gasoline cargoes to the U.S. and product shipments to Argentina.

In April last year, rates reached their highest since 2008 on a jump in U.S. gasoline demand. Since then, average earnings have remained volatile.

Long Range 1 tankers, carrying 55,000-tonne loads from the Middle East Gulf (MEG) to Japan, were at W94.23 or $5,055 a day.

That compared with W94.20 or $5,362 a day on Tuesday and W94.38 or $3,848 a day last Wednesday.

Larger Long Range 2 or LR2, 75,000-tonne shipments on the Middle East Gulf to Japan route were at W73.76 or $3,820 a day. That compared with W73.45 or $4,196 a day on Tuesday and W75.00 or $3,270 a day last Wednesday.

"Aware that fundamentals remain strongly in charterers' favour, LR2 owners in the MEG have been able to offer little resistance as eastbound rates fall further," broker SSY said.

Late last year the volume of LR1 fixtures jumped to their highest in years, helped by healthy naphtha and jet fuel bookings to Asia, sending earnings to their highest since early October 2009.