Are you looking for some big returns for your investment portfolio?

If you are, then it could pay to listen to what Goldman Sachs is saying about the ASX 200 shares in this article.

The broker has named them as buys and tipped them to rise 35%+ from current levels. Here's what the broker is recommending:

Champion Iron Ltd (ASX: CIA)

Goldman is feeling positive about iron ore miner Champion Iron. This morning, the broker has put a buy rating and $7.60 price target on the ASX 200 share. Based on its current share price of $5.55, this implies potential upside of 37% over the next 12 months.

Goldman believes that its shares are undervalued at current levels. It said:

Attractive valuation: the stock is trading at ~0.65x NAV (A$8.53/sh) and ~4.5x EBITDA (NTM). Our NAV is based on our long run Fe price of ~US$80/t (real) for 62% Fe and a US$50/t CIA average product premium assumption over 62% Fe benchmark. For every ~US$10/t increase in our long run price, our CIA NAV would increase by ~A$1.5/sh.

In addition, it highlights that the company's earnings are about to get a boost from the Bloom Lake ramp up. Goldman adds:

Bloom Lake operating at around nameplate 15Mtpa, de-bottlenecking options to 18Mtpa: CIA has now ramped-up Bloom Lake Phase II to 15Mtpa nameplate, and we expect this to support +30% EBITDA & OCF growth in FY26, which could fund de-bottlenecking of Bloom Lake to 18Mtpa (not included in GSe base case).

Karoon Energy Ltd (ASX: KAR)

Another ASX 200 share that gets the thumbs up from Goldman Sachs is energy producer Karoon Energy.

This morning, the broker has retained its buy rating on the company's shares with an improved price target of $2.08. Based on its current share price of $1.54, this suggests that upside of 35% is possible for investors.

Much like Champion Iron, the broker feels that Karoon Energy's shares are undervalued. It said:

Attractive valuation: KAR is trading at a ~35% discount to our risked NAV, which we feel does not reflect the value of producing assets and the potential Neon development, where our unrisked NAV including 100% of Neon is A$3.34/sh.

Another positive is that a good dividend yield looks possible this year according to the broker. It adds:

Trading on a ~9% FCF yield over 2025E supported by our expectations for oil prices to remain stable over the near term, where KAR offers unique exposure to oil prices within the Australian Energy sector and is trading on a 5% 2025E dividend yield.