CSL Ltd (ASX: CSL) shares couldn't avoid the broader market sell-off on Monday.

Shares in the S&P/ASX 200 Index (ASX: XJO) biotech stock ended the day down 1.4%, trading for $276.42 apiece.

That sees CSL shares down 7.9% since this time last year, underperforming the 9.9% 12-month gains posted by the ASX 200. Modestly softening those losses for shareholders, the biotech stock also trades on a 1.4% unfranked trailing dividend yield.

With that lacklustre year of performance behind it, here's why these two investing experts are optimistic on the outlook for CSL in 2025 (courtesy of The Bull).

The bullish case for CSL shares

"CSL is a global biotechnology company," said Sequoia Wealth Management's Peter Day, who has a buy recommendation on CSL shares.

He added:

Its medicines treat haemophilia and immune deficiencies. Its vaccines prevent influenza. It provides therapies in iron deficiency and nephrology. CSL provides products to more than 100 countries.

Explaining his optimistic outlook for CSL stock, Day said, "The company has posted a significant increase in revenue during the past three years and delivered earnings growth that's compounding at double-digit rates."

Revenue and earnings growth count as the first reason you may want to consider buying CSL shares today.

As for the second reason, Day said, "CSL was recently trading on a modest and appealing price/earnings ratio, which provides valuation support at current levels."

At Monday's close, CSL was trading at a P/E ratio of approximately 32 times.

Time for a rebound?

Catapult Wealth's Dylan Evans also has a buy recommendation on CSL shares. And he's expecting a rebound for the ASX 200 biotech company after a long stretch of underperformance.

"The share price of this blood products company has been a disappointing performer," he said.

Evans noted that "The shares have fallen from $320.03 on February 3, 2020, to trade at $276.77 on January 30, 2025."

And he said this didn't appear to stack up against the company's financial performance.

Which is the third reason CSL shares look like a good buy today.

According to Evans:

The company generated full year 2024 net profit after tax of $2.75 billion at constant currency, up 25% on the prior corresponding period. CSL is a high-quality defensive stock, anticipating double digit earnings growth in fiscal year 2025 amid trading on a relatively modest earnings multiple.

The patience of long-term investors has certainly been tested, but we expect good returns going forward.

CSL reported its FY 2024 results on 13 August.

Atop growing profits, the company achieved revenue growth of 11% in constant currency to US$14.8 billion.