According to The Wall Street Journal, Verizon contacted the unnamed retailers last week.
It's not clear which retailers may be involved in these subsequent breaches.
New York-based Verizon did not immediately respond to a request for comment.
Earlier on Wednesday, Target revealed its quarterly profits tumbled by nearly half due to the fallout of the massive data breach, which is believed to be one of the largest credit-card thefts on record.
Hackers infiltrated Target by stealing credentials from a refrigeration contractor, resulting in the compromise of 40 million credit and debit card accounts and the personal data of up to 70 million people.
The Minneapolis-based retailer said it was hit by $61 million of total expenses tied to the breach.