While Nordstrom dropping Ivanka Trump merchandise got a lot of headlines, it's not the only online retail partner seeing slower sales for the brand. According to an analysis of email receipts by Slice Intelligence, online, Nordstrom sells the most by revenue, followed by Macy's.com , third is Zappos.com (owned by Amazon ), Amazon (where most is sold by third-party sellers) is fourth, and Bloomingdale's.com (owned by Macy's) rounds out the top five. (Slice Intelligence analysis comes from a panel of 4.4 million online shoppers.)

Nordstrom said its decision wasn't political, it was business. The Slice Intelligence data appears to back up that claim, with Ivanka Trump merchandise sales down, at least online, for Nordstrom.

On Wednesday, the department store further clarified its decision not to place new orders for the brand because sales have been "steadily declining" particularly in the second half of 2016, and it no longer makes "good business sense" to continue selling the line at this time.



Ivanka Trump merchandise sales did, however, grow 30 percent online at Macys.com and 9 percent on Bloomingdales.com in the fourth quarter compared to the prior year, but the growth was sharply lower than the growth rate seen in the first half of 2016.



There was a spike in sales on the Nordstrom website in July 2016, following Ivanka Trump's appearance at the Republican National Convention, but not on the other four top websites for her brand sales.

Slice Intelligence said sales during the week of July 17, 2016, rose two-and-a-half times the previous week on Nordstrom.com, but the majority of the purchases driving the spike were shoes, not the dress she wore while giving her speech at the convention.



CNBC has reached out to the retailers for comment, but had not yet received a response.



For the Ivanka Trump brand, it's unknown what portion of sales online transactions represent. However, generally speaking, the vast majority of retail sales are still done in physical stores. For example, more than 21 percent of Nordstrom's total sales are online, which is high for a traditional retailer, while Macy's online sales are around 17 percent of its total sales, according to eMarketer.

Ivanka Trump's brand is a private company, but publicly traded G-III Apparel Group has a license agreement with the brand to design and source the goods, which are sold at more than 20 retail stores and websites. Experts say a ballpark estimate for annual total sales for Ivanka Trump goods is less than $100 million. No financial details have been made public regarding the sales of Trump's merchandise at the various retail partners.



Retail experts say the business at Nordstrom is likely not large enough to be considered "material" so neither the department store nor G-III Apparel Group will likely disclose further financial details of the severed relationship.