We investigate the sources of betting constructions, and specifically their predicates. The notion of risking something of value on an outcome is a complex one. Culturally, some degree of disposability of property is required. The concept is nevertheless lexicalized in many parts of the world. Betting takes various forms, ranging from betting between individuals, which we contend is the basic case, to betting in the context of an institution such as horse racing, cockfighting, lotteries, or on games such as card games. Taking a similar approach to Zalizniak (2008), we use polysemy as a means of investigating etymology. A sample of 271 polysemous predicates from 177 languages are surveyed, where one sense is BET. Treating relevant other senses as earlier senses, we find that the most frequent source concepts are ones that profile (in Langacker's 2008 sense) the relation between the bettor and the stake. The most frequent are SECURITY and PUT. Other important sources, profiling instead the relation between the bettors, are ARGUE, COMPETE and AGREE.