Dive Brief:

• In 2019, 51.3% of U.S. households will possess Amazon Prime memberships, translating to about 63.9 million households overall. That number is about 5.2 million more households than last year, according to a new eMarketer study.

• The report states that growth in Prime memberships will be powered by lower-income households and other consumers drawn to Amazon's recent support for installment payments and new program offerings.

• Amazon Household, a program that allows different members of a single household, including teens, to have their own log-in for shopping and viewing of Prime content, was specifically cited by eMarketer as a factor driving adoption.

Dive Insight:

Counting the number of households with Prime memberships offers a new way of thinking about Amazon's vast ecosystem influence. The increasing hold that Amazon's Prime program has could be significant as the e-commerce giant gets more deeply involved in the smart home market, for example.

Its partners, particularly those who have signed up to integrate the Alexa virtual assistant or Dash automated replenishment into their own branded appliances, are likely to be pleased with its positioning around Prime households (though sales of physical dash buttons have recently ceased). More broadly, the Prime household base could influence how Amazon chooses to promote specific products, everything from its own devices to commonly-sold household items.

The Consumer Intelligence Research Partners (CIRP) last year reported that Prime memberships were flattening in the U.S., but Prime users still spend an average of $1,400 annually on Amazon purchases, more than double what non-Prime members spend. More instances of multiple purchasers on one or more Prime memberships in a particular household could continue to drive that number upward, regardless of whether or not growth in individual Prime membership sign-ups continues to slow.