Forbes’ Rich List Prudent

Forbes magazine says its estimates of the net worth of what it considers the 400 wealthiest Americans are “deliberately conservative.”

The magazine said its basic principle in compiling the estimates was to “think in terms of how much a prudent buyer . . . might be willing to pay for a person’s net assets.”

Among the factors used in compiling the estimates, which Forbes released Monday:

- Blocks of publicly traded stock were priced at the market close Sept. 8.

- Privately held companies were valued according to estimated revenues and earnings and to prevailing price-earnings ratios for publicly traded companies in similar businesses.

- If earnings and cash flow weren’t known, the magazine said, it adopted valuations typically used in particular industries.

- For trusts and other inter-family arrangements, Forbes said it worked on a case-by-case basis, “applying common sense.”

“The fortunes of the very rich are, of course, very difficult to calculate,” Forbes said. “Often it isn’t even clear exactly who owns a great fortune.”