Amazon is turning to third-party sellers to expand one of its fastest shipping options — and asking them to pay up for it.

The e-commerce giant is asking some sellers who use Fulfillment by Amazon, or FBA, to submit bids to make their products eligible for “sub-Same Day” delivery, according to an email sent to sellers earlier this month.

Sub-Same Day deliveries arrive as soon as two hours after customers place an order and are available in 2,300 metro areas, according to Amazon. Items sold through sub-Same Day delivery “have experienced 12% higher sales on average” than those delivered through regular FBA service, Amazon wrote in the email.

“You…