John L. Kelly Jr.
John Larry Kelly Jr. (1923–1965) was a Bell Labs scientist who wrote the 1956 paper that became the Kelly criterion — originally an information-theory result, not a trading book.
The 1956 Paper
"A New Interpretation of Information Rate" (Bell System Technical Journal) asked how a gambler with noisy advance tips on horse races should bet when odds are fair but tips are imperfect. Kelly showed maximizing expected log wealth yields a proportional betting policy that avoids ruin while exploiting edge.
The paper also hinted at stock-market application: favorable equity bets are "investments"; unfavorable ones are "gambling" — differing by what Kelly's colleague Elwyn Berlekamp summarized as a minus sign.
Lineage
- Shannon refereed the paper and later passed it to Thorp.
- Breiman (1961) generalized Kelly's asymptotic optimality.
- Popular history: fortunes-formula.
Kelly died young (1965, brain hemorrhage while walking). His formula outlived him through Thorp, hedge funds, and the geometric-mean portfolio debate.
Connections
- Claude-Shannon
- Edward-Thorp
- kelly-criterion
- the-kelly-criterion-thorp-2006
- fortunes-formula