Promotion on Mercado Livre: the cost-sharing almost no one checks

There’s a type of promotion on Mercado Livre where the platform pays part of the discount, deducting it from the commission you’d pay. In these campaigns, a discounted sale can leave you with more margin than a full-price sale. On a R$ 100 product with a 12% commission, a promotion at R$ 89 with ten points of cost-sharing leaves you R$ 28.33, versus R$ 26.45 for the R$ 100 sale. The discount came out of Mercado Livre’s pocket.

Here’s the uncomfortable part: the promised refund doesn’t always show up in your statement. And since almost no one checks order by order, stores spend months thinking they ran a cost-shared promotion when they actually gave the discount alone.

#Not all promotions are the same

The Promotions Center puts very different things under the same button. There are individual discounts that come entirely out of your price. There are flash deals and daily deals, which trade margin for exposure. There are seller campaigns, which you set up. And there are campaigns with Mercado Livre’s participation, where the platform covers part of the discount.

The difference between these groups isn’t intensity—it’s nature. In one, you fund the discount. In the other, you split it. Treating all of them the same is the basic mistake.

Before accepting any campaign invite, there’s only one question: who’s paying for this discount?

#The calculation in all three scenarios

300-gram product, 12% commission, 6% tax, R$ 40.60 cost including packaging:

Look at the second row. A 15% discount without platform support eats up 39% of your margin. That’s why a poorly chosen promotion drains your cash even when sales volume goes up.

And look at the last one. The same discount, with platform support, can bring in more than a full-price sale. Two decisions that look the same on screen but are opposites on your statement.

#How to check if cost sharing happened

This is the habit I wish more people had, and it takes just ten minutes.

Pick five orders sold during the campaign. Open the fee details for each one. Compare the commission charged to the normal commission for your category. If the full commission was charged, there was no refund on that order.

Do this in the first week of every campaign, not at the end. If the refund isn’t happening, you still have time to get out.

In practice. A seller showed me three months of campaign statements with promised cost sharing. Zero commission refunds. None. He gave real discounts on hundreds of orders thinking the cost was split. The loss wasn’t the promotion—it was not checking in the first month.

#When to join and when not to

Join when cost sharing is real and the promo price is still above your minimum. Also join if you have slow-moving stock with high coverage and need to turn inventory into cash, even with a low margin. It’s a valid financial decision, as long as it’s conscious.

Don’t join with products that already sell well organically and have tight stock. You’re giving discounts to people who would buy anyway.

And watch out for a price detail: if the discount drops the product from R$ 85 to R$ 78, you cross the R$ 79 threshold and the shipping cost drops too. In this case, the discount hurts much less than it seems, so it’s worth simulating before ruling it out. I explained this threshold in the article about free shipping.

#Leaving is harder than joining

Good to know in advance: ending participation isn’t always one click. In some campaigns, you have to remove items one by one, and flash or daily deals have a fixed duration.

The practical result is that your decision to join needs to consider the full campaign period, not just the first week. If the campaign lasts thirty days, calculate the margin for all thirty days.

Inside Milewa, the margin for each order already uses the actual commission charged, not the table rate, so cost sharing that didn’t happen shows up as a margin drop the same day—no need to check order by order.