The first stock index fund turns 50

• Most of us are socking away money in these things automatically through 401(k) payroll deductions.
• Initially called the First Index Investment Trust, the fund launched on Aug. 31, 1976 — the dawn of the passive investing era.

Flashback: Vanguard founder John Bogle raised just $11.3 million at the fund's launch, short of his $150 million target. At the time, people liked to invest in actively managed funds.

• Skeptical investors labeled the endeavor "Bogle's Folly."

Between the lines: Americans love a good folly, however, as Bogle himself pointed out in a speech in 2004.

• Also labeled as follies: William Seward's purchase of Alaska, the Erie Canal and Robert Fulton's steamboat.

By the numbers: More than $18 trillion was held in equity index funds and ETFs, as of June, compared with about $12 trillion in actively managed funds, per ICI.

• The Vanguard 500 has about $1.7 trillion in assets under management, as of July 31.
• A $10,000 investment at launch would have grown to $2.4 million by July 31, Vanguard notes in a press release Monday morning.