Bank of America Merrill Lynch analyst Justin Post said that Yahoo's (YHOO) disclosure of the massive data breach impacting over 500M of its users is clearly a negative for the company that could result in email account closures, but he does not anticipate a major impact on Yahoo's business related to this breach, citing as evidence the fact that he is not aware of any significant business impairment or financial liability related to security breaches at LinkedIn (LNKD) in 2012 and at eBay (EBAY) in 2014.

Post adds that the Target (TGT) data breach, which did include credit card info, is not directly comparable to Yahoo's breach.

For Verizon (VZ) to back out of its acquisition agreement, Post thinks the company would need to assume Yahoo acted in bad faith during negotiations and that the Yahoo asset is impaired or comes with significant liability, neither of which he sees as being the case.

The analyst keeps a Buy rating on Yahoo and bumped his target on the shares to $55 from $53, citing an increased price target on Alibaba (BABA) that a peer at the firm recently set.