Subject: Re: Margin debt
The term "Broker's Loan" bis essentially what we would call "margin: today (and leverage of 90% was permitted)

From "The Great Crash 1929" by John Kenneth Galbraith:

Excerpted from: CHAPTER IV, The Twilight of Illusion

More than the prices of common stocks were rising. So, at an appalling
rate, was the volume of speculation. Brokers' loans during the summer
increased at a rate of about $400,000,000 a month. By the end of the
summer, the total exceeded seven billions. Of that more than half was
being supplied by corporations and individuals, at home and abroad, who
were taking advantage of the excellent rate of return which New York was
providing on money. Only rarely did the rate on call loans during that
summer get as low as six per cent. The normal range was seven to twelve.
On one occasion the rate touched fifteen. Since, as earlier observed, these
loans provided all but total safety, liquidity, and ease of administration,
the interest would not have seemed unattractive to a usurious
moneylender in Bombay. To a few alarmed observers it seemed as though
Wall Street were by way of devouring all the money of the entire world.
However, in accordance with the cultural practice, as the summer passed,
the sound and responsible spokesmen decried not the increase in brokers'
loans, but those who insisted on attaching significance to this trend. There
was a sharp criticism of the prophets of doom.

Scholars also reacted against those who, deliberately or otherwise, were
sabotaging prosperity with their unguarded pessimism. After soberly
viewing the situation, Professor Dice concluded that the high level of
brokers' loans should not be "as greatly feared as some would have us
believe." 3 In August the Midland Bank of Cleveland made public the
results of calculations which proved that until loans by corporations in the
stock market reached twelve billion there was no cause for concern.4
The best reassurance on brokers' loans was in the outlook for the
market. If stocks remained high and went higher, and if they did so
because their prospects justified their price, then there was no occasion to
worry about the loans that were piling up. Accordingly, much of the
defense of the loans consisted in defending the levels of the market. It was
not hard to persuade people that the market was sound; as always in such
times they asked only that the disturbing voices of doubt be muted and
that there be tolerably frequent expressions of confidence.

Jeff