The first company delighting its shareholders in the nascent days of 2026 is BlueScope Steel Ltd (ASX: BSL).

Shares of the painted and coated steel products manufacturer concluded the previous Friday's session at $24.14. Presently, the stock is trading at $30 per share, marking a substantial 24% weekly surge for this ASX 200 constituent.

The majority of these gains materialized on Tuesday.

BlueScope shares skyrocketed 20.8% in a single day after the company disclosed a Non-Binding Indicative Offer from a consortium of SGH Ltd (ASX: SGH) and US-based Steel Dynamics Inc (NASDAQ: STLD) to acquire all of its shares.

The takeover bid from SGH and Steel Dynamics proposed $30 per share in cash, valuing BlueScope at a significant $13.2 billion.

However, BlueScope's board might be anticipating a superior offer, stating they are still evaluating the proposal.

Commenting on the offer, SGH CEO Ryan Stokes remarked:

We believe BlueScope's Australian operations are a powerful strategic complement to SGH, and we have a demonstrated history of enhancing performance in domestic industrial enterprises. Our plan is to apply our disciplined operating framework and capital allocation strategy to achieve superior outcomes for all stakeholders.

This leads to the second ASX 200 stock experiencing a meteoric rise this week, Liontown Resources Ltd (ASX: LTR).

Liontown shares finished last Friday at $1.62. The stock now trades at $2.05 apiece, propelling its share price upward by an impressive 27% for the week.

No new announcements were released by the Australian lithium miner. Nonetheless, lithium prices have climbed approximately 14% since last Friday, driven by anticipations of rising demand, particularly from China. Lithium carbonate is currently trading at its highest price point since November 2023.

Progressing to the top-performing ASX 200 stock on this week's list, we encounter Codan Ltd (ASX: CDA).

Shares in the communications and metal detection firm ended last week at $29.02 and are presently trading for $36.90 each. This translates to a remarkable 27% ascent for the Codan share price during the inaugural full trading week of 2026.

A significant portion of these gains occurred today.

Codan shares have surged 16.9% on Friday, following the release of robust, unaudited H1 FY 2026 results from the ASX 200 company.

Key highlights for the six-month period feature a 29% year-on-year revenue increase to approximately $394 million.

Regarding profitability, Codan's underlying net profit after tax (NPAT) leaped roughly 52% compared to H1 FY 2025, reaching "not less than" $70 million.