• by Joe Mandese  @mp_joemandese, June 17, 2015

The U.S. advertising marketplace expanded in May after a dip in April, following a seasonal pattern that has held steady for the past several years. If the seasonal pattern continues, total ad volume should see relative declines this month and through the summer before it builds again heading into the fall when many major categories begin seasonal marketing pushes.

The data, which can be interacted with dynamically by scrolling over the accompanying U.S. Ad Market Tracker, is based on actual media buys processed by Standard Media Index representing more than 80% of spending from the major agency holding companies.

On a year-over-year basis, however, May’s total ad volume slid 2% from May 2014, which may indicate part of a broader, long-term shift toward non-traditional sources of marketing spending. In fact, “digital” media spending expanded the most on a year-over-year basis, rising 24% over May 2014.

Digital’s expansion appears to support recent pronouncements and speculation that marketers may have hit an inflection point and are beginning to shift budgets from traditional media, especially television. TV ad volume declined 5% from May 2014, as did SMI’s “Top 50” media company composite, much of which includes big media companies that are heavily invested in television.

Within digital, programmatic was one of the fastest-growing sectors, with ad exchanges and ad networks expanding 33% over May 2014. But the fastest growing sector continues to be social, which expanded 59% year-over-year, partly due to more programmatic trading via Facebook’s exchange.