Even before the shortage crisis, baby formula availability was limited in America. Only a few large corporations are permitted by the Food and Drug Administration (FDA) to produce and sell it in this country, which means that one recall or plant shutdown can send the entire market tanking.

According to The Wall Street Journal, heavy regulations combined with the government's WIC (Women, Infants, and Children) program have whittled the baby formula market down to two main players: Similac and Enfamil. These two brands control the bulk of America's "inflexible" $4 billion market for baby formula.

"Baby formula is one of the most tightly regulated food products in the country," write Jesse Newman and Annie Gasparro.

"That makes the barrier to new entrants high, and few brands have emerged as challengers to Similac and Enfamil, made by Abbott Laboratories and Reckitt Benckiser Group, respectively, since the two entered the market in the 1950s."

It turns out that Abbott and Reckitt are responsible for about 80 percent of infant formula sales last year, according to market research group Euromonitor.