This article is part of our Rising Star Portfolios series.

Over the next couple of days, I'll be gathering more small- and mid-cap candidates for my Rising Star "multivitamin" portfolio using my Foolish 8 and modified Foolish 8 screens. Today I present the Foolish 8, which was developed by Motley Fool co-founder David Gardner to identify profitable, rapid-growth, small-cap stocks. Here are the eight criteria:

  1. Revenues: $500 million or less.
  2. Earnings and sales growth: 25% or greater.
  3. Net profit margin: 7% or greater.
  4. Daily dollar volume: $1 million to $25 million.
  5. Insider holdings: 10% or greater.
  6. Share price: $7 or greater.
  7. Relative strength: 90 or greater.
  8. Operating cash flow: a positive number.

The contenders
Six companies passed the screen this month:

Company

Market Cap
(in Millions)

Business

Add to Your Watchlist

3-D Systems (NYSE: DDD) $800 3-D printers and products Add
Acme Packet (Nasdaq: APKT) $3,128 Communications equipment Add
Interactive Intelligence
(Nasdaq: ININ)
$653 Business software Add
IPG Photonics (Nasdaq: IPGP) $2,720 Networking equipment Add
SolarWinds (NYSE: SWI) $1,577 Business software Add
Virtusa (Nasdaq: VRTU) $367 IT consulting Add

Source: Capital IQ, a division of Standard & Poor's.

SolarWinds is the only new stock on the list this month. Seven dropped off from last month: Financial Engines, Gulfport Energy (Nasdaq: GPOR), HFF, Houston American Energy, Nanometrics, Preformed Line Products, and Transcend Services.

Biggie smalls
Here's a look at some interesting metrics for these small fries:

Company

Insider Ownership

Forward P/E

EV/FCF (TTM)

ROE

Net Margin

3-D Systems 12% 45.7 25.9 21% 18%
Acme Packet 17% 64.3 NM 16% 19%
Interactive Intelligence 24% 25.5 43.7 18% 9%
IPG Photonics 26% 54.1 NM 27% 23%
SolarWinds 23% 29.9 23.9 30% 31%
Virtusa 13% 22.0 99.0 9% 8%

Source: Capital IQ, a division of Standard & Poor's. P/E = price-to-earnings ratio; EV = enterprise value; FCF = free cash flow; TTM = trailing 12 months; ROE = return on equity. NM = not meaningful because of negative free cash flow.

If any of these companies look interesting enough for me to research further, I'll delve more into the reasoning behind the negative FCF.

Tomorrow, I'll show you the results of this month's modified Foolish 8 screen and then talk about the companies that interest me from both screens in more depth.

If you're interested in keeping up with any of these companies, add them to your free watchlist by clicking the "add" button in the far-right column of the top table. You can also follow me on Twitter and check out the multivitamin discussion board. Until tomorrow!

This article is part of our Rising Star Portfolios series, where we give some of our most promising stock analysts cold, hard cash to manage on the Fool's behalf. We'd like you to track our performance and benefit from these real-money, real-time free stock picks. See all of our Rising Star analysts (and their portfolios).

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.