These were the best performing ASX 200 shares last week

It was a mixed week for the S&P/ASX 200 Index (ASX: XJO). A pullback on Friday led to the benchmark index ending the period marginally lower at 7,392.6 points.

This couldn't stop some ASX 200 shares from charging higher over the period. Here's why these were the best performers on the index last week:

Lynas Rare Earths Ltd (ASX: LYC)

The Lynas share price was the best performer on the ASX 200 last week with a 14.2% gain. Investors were fighting to get hold of the rare earths producer's shares following the release of its fourth quarter update. Lynas reported a 79.7% increase in quarterly neodymium and praseodymium (NdPr) production to 1,393 tonnes. Combined with the almost doubling of its average realised price, this led to a significant increase in quarterly sales revenue to $185.9 million. This was up materially from sales revenue of $38 million a year earlier.

Champion Iron Ltd (ASX: CIA)

The Champion Iron share price wasn't far behind with a gain of 12.4% over the five days. This was driven by the release of an impressive first quarter update by the Canadian iron ore producer. Champion Iron more than doubled its revenue to C$545.4 million thanks to a significant increase in its average realised selling price. This ultimately led to record first quarter operating earnings of C$405.7 million, up from C$130.2 million a year earlier.

IRESS Ltd (ASX: IRE)

The IRESS share price was a strong performer and charged 9.3% higher last week. The catalyst for this was news that the financial technology company has received another takeover approach. According to the release, EQT Fund Management has made an unsolicited, non-binding and indicative proposal to acquire IRESS for between $15.30 and $15.50 cash per share. This represented a 22.3% to 23.9% premium to the IRESS share price at the time of the announcement. Last month IRESS rejected a $14.80 per share proposal from EQT.

OZ Minerals Limited (ASX: OZL)

The OZ Minerals share price was on form and jumped 9.3% over the period. Investors were buying the copper producer's shares after the release of its strong second quarter update. OZ Minerals achieved copper production of 32,681 tonnes and gold production of 57,875 ounces during the three months. This led to management making positive revisions to its FY 2021 guidance. It has increased its gold production guidance and reduced its overall cash costs guidance.