Proto Labs (STU:PRZ) Piotroski F-Score: 9 (As of Jul. 12, 2026) — 50% Above Median

Proto Labs  (STU:PRZ) Piotroski F-Score Explanation

The developer of the system is Joseph D. Piotroski is relatively unknown accounting professor who shuns publicity and rarely gives interviews.

He graduated from the University of Illinois with a B.S. in accounting in 1989, received an M.B.A. from Indiana University in 1994. Five years later, in 1999, after earning a Ph.D. in accounting from the University of Michigan, he became an associate professor of accounting at the University of Chicago.

In 2000, he wrote a research paper called "Value Investing: The Use of Historical Financial Statement Information to Separate Winners from Losers" (pdf).

He wanted to see if he can develop a system (using a simple nine-point scoring system) that can increase the returns of a strategy of investing in low price to book (referred to in the paper as high book to market) value companies.

What he found was something that exceeded his most optimistic expectations.

Buying only those companies that scored highest (8 or 9) on his nine-point scale, or F-Score as he called it, over the 20 year period from 1976 to 1996 led to an average out-performance over the market of 13.4%.

Even more impressive were the results of a strategy of investing in the highest F-Score companies (8 or 9) and shorting companies with the lowest F-Score (0 or 1).

Over the same period from 1976 to 1996 (20 years) this strategy led to an average yearly return of 23%, substantially outperforming the average S&P 500 index return of 15.83% over the same period.

Proto Labs Piotroski F-Score Related Terms

The historical data trend for Proto Labs's Piotroski F-Score can be seen below:

* For Operating Data section: All numbers are indicated by the unit behind each term and all currency related amount are in USD.
* For other sections: All numbers are in millions except for per share data, ratio, and percentage. All currency related amount are indicated in the company's associated stock exchange currency.

Proto Labs Piotroski F-Score Chart

Proto Labs Annual Data
	Trend	Dec16	Dec17	Dec18	Dec19	Dec20	Dec21	Dec22	Dec23	Dec24	Dec25
Piotroski F-Score		Get a 7-Day Free Trial					5.00	4.00	7.00	8.00	7.00

Proto Labs Quarterly Data
	Jun21	Sep21	Dec21	Mar22	Jun22	Sep22	Dec22	Mar23	Jun23	Sep23	Dec23	Mar24	Jun24	Sep24	Dec24	Mar25	Jun25	Sep25	Dec25	Mar26
Piotroski F-Score	Get a 7-Day Free Trial															6.00	6.00	6.00	7.00	9.00

STU:PRZ vs RYZ, WOR, MEC: Piotroski F-Score Comparison

For the Metal Fabrication subindustry, Proto Labs's Piotroski F-Score, along with its competitors' market caps and Piotroski F-Score data, can be viewed below:

* Competitive companies are chosen from companies within the same industry, with headquarter located in same country, with closest market capitalization; x-axis shows the market cap, and y-axis shows the term value; the bigger the dot, the larger the market cap. Note that "N/A" values will not show up in the chart.

Proto Labs Piotroski F-Score vs Industrial Products Industry

For the Industrial Products industry and Industrials sector, Proto Labs's Piotroski F-Score distribution charts can be found below:

* The bar in red indicates where Proto Labs's Piotroski F-Score falls into.

How is the Piotroski F-Score calculated?

* For Operating Data section: All numbers are indicated by the unit behind each term and all currency related amount are in USD.
* For other sections: All numbers are in millions except for per share data, ratio, and percentage. All currency related amount are indicated in the company's associated stock exchange currency.

*Note: If the latest quarterly/semi-annual/annual total assets data is 0, then we will use previous quarterly/semi-annual/annual data for all the items in the balance sheet.

Profitability

Question 1. Return on Assets (ROA)

Net income before extraordinary items for the year divided by Total Assets at the beginning of the year.

Score 1 if positive, 0 if negative.

Proto Labs's current Net Income (TTM) was 22.1. ==> Positive ==> Score 1.

Question 2. Cash Flow Return on Assets (CFROA)

Net cash flow from operating activities (operating cash flow) divided by Total Assets at the beginning of the year.

Score 1 if positive, 0 if negative.

Proto Labs's current Cash Flow from Operations (TTM) was 63.2. ==> Positive ==> Score 1.

Question 3. Change in Return on Assets

Compare this year's return on assets (1) to last year's return on assets.

Score 1 if it's higher, 0 if it's lower.

Proto Labs's return on assets of this year was 0.03243464. Proto Labs's return on assets of last year was 0.01925676. ==> This year is higher. ==> Score 1.

Question 4. Quality of Earnings (Accrual)

Compare Cash flow return on assets (2) to return on assets (1)

Score 1 if CFROA > ROA, 0 if CFROA <= ROA.

Proto Labs's current Net Income (TTM) was 22.1. Proto Labs's current Cash Flow from Operations (TTM) was 63.2. ==> 63.2 > 22.1 ==> CFROA > ROA ==> Score 1.

Funding

Question 5. Change in Gearing or Leverage

Compare this year's gearing (long-term debt divided by average total assets) to last year's gearing.

Score 0 if this year's gearing is higher, 1 otherwise.

Proto Labs's gearing of this year was 0.0018063. Proto Labs's gearing of last year was 0.00225463. ==> This year is lower or equal to last year. ==> Score 1.

Question 6. Change in Working Capital (Liquidity)

Compare this year's current ratio (current assets divided by current liabilities) to last year's current ratio.

Score 1 if this year's current ratio is higher, 0 if it's lower

Proto Labs's current ratio of this year was 3.51481814. Proto Labs's current ratio of last year was 3.13100026. ==> This year's current ratio is higher. ==> Score 1.

Question 7. Change in Shares in Issue

Compare the number of shares in issue this year, to the number in issue last year.

Score 0 if there is larger number of shares in issue this year, 1 otherwise.

Proto Labs's number of shares in issue this year was 24.287. Proto Labs's number of shares in issue last year was 24.436. ==> There is smaller number of shares in issue this year, or the same. ==> Score 1.

Efficiency

Question 8. Change in Gross Margin

Compare this year's gross margin (Gross Profit divided by sales) to last year's.

Score 1 if this year's gross margin is higher, 0 if it's lower.

Proto Labs's gross margin of this year was 0.44856376. Proto Labs's gross margin of last year was 0.44336311. ==> This year's gross margin is higher. ==> Score 1.

Question 9. Change in asset turnover

Compare this year's asset turnover (total sales for the year divided by total assets at the beginning of the year) to last year's asset turnover ratio.

Score 1 if this year's asset turnover ratio is higher, 0 if it's lower

Proto Labs's asset turnover of this year was 0.68830784. Proto Labs's asset turnover of last year was 0.65361844. ==> This year's asset turnover is higher. ==> Score 1.

Evaluation

Good or high score = 7, 8, 9
Bad or low score = 0, 1, 2, 3

Proto Labs has an F-score of 9. It is a good or high score, which usually indicates a very healthy situation.

Proto Labs Business Description