Are you on the lookout for some new additions to your portfolio in December?

If you are, it could pay to look at the two ASX 300 shares that brokers have just put buy ratings on.

Here's what they are saying about them:

Monash IVF Group Ltd (ASX: MVF)

Morgans thinks that this ASX 300 share could be fertile ground to grow an investment.

The broker likes Monash IVF, which is one of the largest fertility clinic operators in the country, due to its attractive valuation and strong structural demand.

Commenting on its recent trading update, the broker said:

MVF has provided a trading update at its AGM for performance YTD (up to October) and has provided guidance for 1H25 of underlying NPAT between $15.5-16.0m and continues to expect both revenue and underlying NPAT growth in FY25. Australian ARS industry cycles were weak in July and August, particularly in VIC, QLD and SA, but have since rebounded to see industry stimulated cycle growth up 2.9%. MVF is tracking slightly below industry, although maintaining market share on the pcp. The South East Asian business continues to gather momentum with strong growth YTD following a strong 2H24.

Despite continued cost pressures, MVF has maintained EBITDA margins YTD largely through patient price increases. We have made minor downward revisions to our earnings but continue to see strong structural demand drivers for MVF, we maintain our Add recommendation with a $1.50 price target (was $1.54).

Based on its current share price of $1.20, this price target implies potential upside of 25% for investors over the next 12 months.

NIB Holdings Limited (ASX: NHF)

This morning, Goldman Sachs has retained its buy rating and $6.50 price target on this health insurance company's shares.

This follows the release of quarterly data which showed that participation rates have improved. Outside this, the broker believes NIB is a buy due to its defensive earnings and favourable trading conditions. It said:

NHF is a private health insurer with operations across Australian residents health insurance, New Zealand health insurance, International health insurance and Travel. We are Buy-rated on NHF given: 1) It offers defensive exposure to the private health insurance sector 2) The claims environment (utilisation / inflation) is generally manageable albeit until recently 3) NHF policyholder growth has been better than industry, 4) Expense buffers available to support margins and 5) Strong approved rate increases.

Based on its current share price of $5.70, Goldman's price target implies potential upside of 14% over the next 12 months. The broker also expects a 4.5% dividend yield in FY 2025.