Over the last decade and a half, CSL Ltd (ASX: CSL) shares have been a great place to park your money.

During this time, the biotechnology giant's shares have generated a total average annual return of 16.4% per annum.

This means that if you had invested $5,000 into CSL's shares all the way back in 2009 and held tightly to them until today, your investment would have grown to be worth a mouth-watering ~$49,000.

This has been driven by the company's consistently strong performance underpinned by its in-demand plasma therapies, acquisitions, and its annual investment in research and development (R&D).

In respect to the latter, CSL reinvests in the region of 12% of its sales back into R&D activities each year. This has led to the development of some lucrative and life-saving therapies and vaccines, as well as a pipeline of future products to drive its growth.

But those gains have been and gone. What could happen if I invested $5,000 into the company's shares today? Would they be a good place to put my hard-earned money? Let's find out what analysts are saying about the biotechnology giant.

The majority of analysts in Australia are positive on CSL and see plenty of value in its shares at current levels.

For example, Morgans has an add rating and $315.40 price target on them. It recently described CSL as a key holding and named it on its best ideas list. The broker commented:

While shares have struggled of late, we continue to view CSL as a key portfolio holding and sector pick, offering double-digit recovery in earnings growth as plasma collections increase, new products get approved and influenza vaccine uptake increases around ongoing concerns about respiratory viruses, with shares trading at 25x, a substantial discount (20%) to its long-term average.

Analysts at UBS and Macquarie see even more value in the company's shares at current levels. They both recently put the equivalent of buy ratings and $330.00 price targets on them.

At present, CSL shares are changing hands for $280.33. This means that for an investment of $5,045.94, I could pick up 18 units.

If those shares were to rise in value to UBS and Macquarie's price targets, they would have a market value of $5,940. That's approximately $900 more than my original investment.

But it gets better. Macquarie is so positive on the outlook for the key CSL Behring business that it believes the CSL share price could climb beyond $500 within three years. If this proves accurate, those 18 shares would have a market value of $9,000 in 2027.

All in all, it seems that the company's shares could be worth holding tightly to for some time to come.