Sifting through countless of stocks in the Biotechnology industry can be tedious, and sometimes two stocks are just too similar to judge which is the better investment. If you’re on the fence about investing in PTC Therapeutics, Inc. or Zymeworks Inc. because you’re not sure how they measure up, it’s important to compare them on a few factors before making your decision.

Read on to learn how PTC Therapeutics, Inc. and Zymeworks Inc. compare based on key financial metrics to determine which better meets your investment needs.

About PTC Therapeutics, Inc. and Zymeworks Inc.

PTC Therapeutics, Inc., a biopharmaceutical company, focuses on the discovery, development, and commercialization of medicines to children and adults living with rare disorders in the United States and internationally. The company offers Translarna and Emflaza for the treatment of Duchenne muscular dystrophy; Upstaza to treat aromatic l-amino acid decarboxylas (AADC) deficiency, a central nervous system disorder; Tegsedi and Waylivra for the treatment of rare diseases; and Evrysdi to treat spinal muscular atrophy (SMA) in adults and children. Its development pipeline products include Sepiapterin for the treatment of phenylketonuria; PTC518 splicing platform, which is being developed for the treatment of Huntington’s disease; and inflammation and ferroptosis platforms, including vatiquinone to treat Friedreich’s ataxia. The company distributes its products through third-party distributors. It has collaborations with F. Hoffman-La Roche Ltd., Hoffman-La Roche Inc., the SMA Foundation, National Taiwan University, Akcea Therapeutics, Inc., and Shiratori Pharmaceutical Co., Ltd. The company has license and collaboration agreement with Novartis Pharmaceuticals Corporation to develop PTC518 Huntington's disease program. It markets Upstaza, a gene therapy with the brand name Kebilidi in the United States. PTC Therapeutics, Inc. was incorporated in 1998 and is headquartered in Warren, New Jersey.

Zymeworks Inc., a clinical-stage biotechnology company, discovers, develops, and commercializes biotherapeutics for the treatment of cancer, and autoimmune and inflammatory diseases (AIID). Its therapeutic platforms and fully integrated drug development engine provides the flexibility and compatibility to precisely engineer and develop highly differentiated antibody-based therapeutic candidates. The company’s platforms include Azymetric multispecific antibody platform; Drug Conjugate platform includes a suite of proprietary cytotoxins comprising topoisomerase and microtubulin inhibiting toxins, stable linkers, and conjugation technologies; EFECT platform, which consists of a set of modifications to the Fc region of antibodies that enable the selective modulation of recruited cytotoxic immune cells for various therapeutic applications; and ProTECT, a tumor-specific immune co-stimulation platform. Its lead product candidate consists of zanidatamab, a novel bispecific antibody that targets human epidermal growth factor receptor 2 HER2 that is in Phase 1, Phase 2, and Phase 3 clinical trials, including certain ongoing pivotal clinical trials; and zanidatamab zovodotin, a HER2 -targeted antibody-drug conjugate that is in Phase 2 clinical trial for the treatment of advanced or metastatic HER2-expressing tumors. In addition, the company develops a pipeline of preclinical product candidates. It has strategic partnerships and collaborations with BeiGene, Ltd.; Celgene Corporation; Celgene Alpine Investment Co. LLC; GlaxoSmithKline Intellectual Property Development Limited; Daiichi Sankyo Co., Ltd.; Iconic Therapeutics, Inc.; Merck Sharp & Dohme Research GmbH; and Atreca, Inc. Zymeworks Inc. was incorporated in 2003 and is based in Middletown, Delaware.

Latest Biotechnology and PTC Therapeutics, Inc., Zymeworks Inc. Stock News

As of December 19, 2025, PTC Therapeutics, Inc. had a $6.3 billion market capitalization, compared to the Biotechnology median of $206.2 million. PTC Therapeutics, Inc.’s stock is up 74.7% in 2025, up 3.4% in the previous five trading days and up 67.1% in the past year.

Currently, PTC Therapeutics, Inc.’s price-earnings ratio is 8.8. PTC Therapeutics, Inc.’s trailing 12-month revenue is $1.8 billion with a 42.3% net profit margin. Year-over-year quarterly sales growth most recently was 7.2%. Analysts expect adjusted earnings to reach $8.817 per share for the current fiscal year. PTC Therapeutics, Inc. does not currently pay a dividend.

As of December 19, 2025, Zymeworks Inc. had a $2.0 billion market cap, putting it in the 56th percentile of all stocks. Zymeworks Inc.’s stock is up 88.9% in 2025, up 6.5% in the previous five trading days and up 103.67% in the past year.

Currently, Zymeworks Inc. does not have a price-earnings ratio. Zymeworks Inc.’s trailing 12-month revenue is $134.5 million with a -47.2% net profit margin. Year-over-year quarterly sales growth most recently was 72.5%. Analysts expect adjusted earnings to reach $-0.873 per share for the current fiscal year. Zymeworks Inc. does not currently pay a dividend.

How We Compare PTC Therapeutics, Inc. and Zymeworks Inc. Stock Grades

Stock evaluation requires access to huge amounts of data and the knowledge and time to sift through it all, make sense of financial ratios, read income statements and analyze recent stock movements. AAII created A+ Investor, a robust data suite that condenses data research in an actionable and customizable way suitable for investors of all knowledge levels, to help investors streamline and work through such data.

AAII’s proprietary stock grades come with A+ Investor. These offer intuitive A‐F grades for each of five key investing factors: value, growth, momentum, earnings estimate revisions and quality. Here, we’ll take a closer look at PTC Therapeutics, Inc. and Zymeworks Inc.’s stock grades to see how they measure up against one another.

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PTC Therapeutics, Inc. and Zymeworks Inc. Growth Grades

Company	Ticker	Growth
PTC Therapeutics, Inc.	PTCT	F
Zymeworks Inc.	ZYME	F

The foundation of growth investing is seeking out stocks of companies exhibiting strong, consistent and prolonged growth that is expected to continue into the future.

In order to compute the growth score and assign it a letter grade, the percentile ranks for each of three components‐consistency of annual sales growth, five-year sales growth rankings adjusted for extreme levels, and consistency of positive annual cash from operations‐must be determined. These three rank figures are added together, and the sum is ranked against the entire stock universe to arrive at a company’s Growth Score to create an equal distribution of grades.

The companies in the bottom 20% of the stock universe receive Growth Grades of F, considered to be very weak, while those in the top 20% receive A grades, which are considered very strong.

PTC Therapeutics, Inc. has a Growth Score of 20, which is Very Weak. Zymeworks Inc. has a Growth Score of 13, which is Very Weak.

The Growth Stock Winner: No Clear Winner

Neither PTC Therapeutics, Inc. or Zymeworks Inc. has a high enough Growth Grade to be considered a “winner.” Investors who are considering these companies should do additional due diligence and research to see if either could be a good addition to their portfolios. It’s important to look at a wide range of financial metrics in order to determine if PTC Therapeutics, Inc. or Zymeworks Inc. is the better investment when it comes to sustainable growth.

PTC Therapeutics, Inc. and Zymeworks Inc.’s Quality Grades

Company	Ticker	Quality
PTC Therapeutics, Inc.	PTCT	A
Zymeworks Inc.	ZYME	D

Like the Value Grade, AAII’s A+ Investor Quality Grade comes from the percentile rank of key metrics. Specifically, the Quality Score is the percentile rank of the average of the percentile ranks of return on assets (ROA), return on invested capital (ROIC), gross profit relative to assets, buyback yield, change in total liabilities to assets, accruals, Z double prime bankruptcy risk (Z) score and the F-Score.

The score is variable, meaning it can consider all eight measures or, should any of the eight measures not be valid, the remaining measures that are valid. To be assigned a Quality Score, stocks must have a valid (non-null) measure and corresponding ranking for at least four of the eight quality measures.

The Quality Score is used to assess the underlying “quality” of a particular stock. A higher-quality stock possesses traits associated with upside potential and reduced downside risk. Backtesting of the Quality Grade shows that stocks with higher grades, on average, outperformed stocks with lower grades over the period of 1998 through 2019.

Stocks receive better grades (higher scores) for having higher scores for the quality subcomponents and worse grades (lower scores) for lower scores for the subcomponents.

PTC Therapeutics, Inc. has a Quality Score of 88, which is Very Strong. Zymeworks Inc. has a Quality Score of 35, which is Weak.

The Quality Grade Winner: PTC Therapeutics, Inc.

As you can clearly see from the Quality Grade breakdown above, PTC Therapeutics, Inc. has a better overall quality grade than Zymeworks Inc.. For investors who are looking for companies with higher quality than others in the same industry, PTC Therapeutics, Inc. could be a good stock to add to their portfolios. However, it’s important for investors to analyze multiple factors based on a wide range of metrics before deciding whether to buy.

PTC Therapeutics, Inc. and Zymeworks Inc.’s Estimate Revisions Grades

Company	Ticker	Earnings Estimate
PTC Therapeutics, Inc.	PTCT	B
Zymeworks Inc.	ZYME	C

Earnings estimate revisions scores consider the magnitude of a company’s earnings surprise in its last two reported fiscal quarters. Often, positive surprises beget further positive surprises‐or at least continued sales growth (the exact opposite is generally true, too).

Estimate revisions offer an indication of what analysts are thinking about the short-term prospects of a firm. Estimate revisions are based on the statistical significance of a firm’s last two quarterly earnings surprises and the percentage change in its consensus estimate for the current fiscal year over the past month and past three months.

PTC Therapeutics, Inc. has a Earnings Estimate Score of 78, which is Positive. Zymeworks Inc. has a Earnings Estimate Score of 58, which is Neutral.

The Earnings Estimate Revisions Grade Winner: PTC Therapeutics, Inc.

As you can clearly see from the Earnings Estimate Revisions Grade breakdown above, PTC Therapeutics, Inc. has a better Earnings Estimate Revisions Grade than Zymeworks Inc.. For those who are specifically looking for companies with better short-term prospects when compared to other companies in the same industry, PTC Therapeutics, Inc. could be a good stock to invest in. However, it’s important to analyze multiple factors based on a wide range of metrics before deciding whether to buy.

Other PTC Therapeutics, Inc. and Zymeworks Inc. Grades

In addition to Estimate Revisions, Growth and Quality, A+ Investor also provides grades for Value and Momentum.

Momentum grades help uncover stocks experiencing anomalously high rates of return; research finds that stocks with high relative levels of momentum tend to outperform, whereas those with low levels of momentum tend to continue underperforming.

Successful stock investing involves buying low and selling high, so stock valuation is an important consideration for stock selection. Buying stocks that are going to go up typically means buying stocks that are undervalued in the first place, although momentum investors may argue that point.

These 2 key factors, when combined with the above, provide a holistic view into a particular stock. Further, by joining A+ Investor you can see whether PTC Therapeutics, Inc. and Zymeworks Inc. pass any of our 60+ stock screens that have outperformed the market since their creation.

So, Which Is the Better Investment, PTC Therapeutics, Inc. or Zymeworks Inc. Stock?

Overall, PTC Therapeutics, Inc. stock has a Growth Score of 20, Estimate Revisions Score of 78 and Quality Score of 88.

Zymeworks Inc. stock has a Growth Score of 13, Estimate Revisions Score of 58 and Quality Score of 35.

Comparing PTC Therapeutics, Inc. and Zymeworks Inc.’s grades, scores and metrics can act as a solid basis to determine whether they may be a good investment or not. You’ll also want to look at your portfolio’s asset allocation as well as your risk tolerance and financial goals to see if either of these stocks would make a good fit for you. AAII can help you figure out which investments align with your individual needs and preferences.

Investors are encouraged to do their own due diligence and research. In this way, individuals can effectively become managers of their own assets‐without having to rely on others for financial independence. You can count on AAII for timeless articles on financial planning and stock-picking, unbiased research and actionable analysis.

A+ Investor adds to our qualitative teaching with a powerful data suite to help you whittle down investment choices to find stocks, exchange-traded funds (ETFs) or mutual funds that meet your needs.

AAII Disclaimer

We make no representations or warranties that any investor will, or is likely to, achieve profits similar to those shown, because past, hypothetical or simulated performance is not necessarily indicative of future results. Before making an investment decision, you should consider your circumstances and whether the information on our content is applicable to your situation. This information was prepared in good faith, and we accept no liability for any errors or omissions. The full disclaimer can be read here.