It was another busy week for Australia's top brokers. This has led to the release of a number of broker notes.

Three broker buy ratings that you might want to know more about are summarised below. Here's why brokers think these ASX shares are in the buy zone:

CSL Ltd (ASX: CSL)

According to a note out of UBS, its analysts have retained their buy rating on this biotechnology company's shares with a slightly reduced price target of $330.00. The note reveals that UBS has trimmed its earnings estimates and valuation to reflect its belief that its vaccines business may not be performing in line with expectations in FY 2025. However, the broker remains very bullish on CSL. This is due to the positive outlook for its key CSL Behring plasma business. UBS feels that consensus estimates are achievable, which is expected to drive solid earnings growth in the coming years. The CSL share price ended the week at $277.55.

Pilbara Minerals Ltd (ASX: PLS)

A note out of Bell Potter reveals that its analysts have upgraded this lithium miner's shares to a buy rating with a $2.95 price target. Bell Potter made the upgrade for a variety of reasons. One was on valuation grounds following a sharp pullback in its share price in recent weeks. In addition, the broker thinks that now could be a good time to invest given how short interest is falling and the outlook for lithium is improving. In respect to the latter, the broker believes that there could be lithium deficits from 2026, which will boost prices. And with Pilbara Minerals having a very strong balance sheet, Bell Potter feels that it is well-placed to respond. The Pilbara Minerals share price was fetching $2.26 at Friday's close.

Pro Medicus Limited (ASX: PME)

Analysts at Goldman Sachs have retained their buy rating on this health imaging technology company's shares with an improved price target of $278.00. According to the note, the broker believes that Pro Medicus is one of Australia's best global growth companies. This is partly based on its belief that further Visage adoption is a matter of when, not if. In light of this, Goldman forecasts a strong increase in the value and cadence of contract wins over time. And while the broker acknowledges that Pro Medicus is not cheap, trading on 114x FY26E EV/EBITDA, it feels that this is justified due to its revenue/margin outlook, unique cloud offering, and significant long-term opportunity. The Pro Medicus share price ended the week at $249.63.