The S&P/ASX 200 Index (ASX: XJO) has fought back from a poor start and is pushing higher. In early afternoon trade, the benchmark index is up 0.2% to 8,425.7 points.

Four ASX shares that are rising more than most today are listed below. Here's why they are climbing:

Dropsuite Ltd (ASX: DSE)

The Dropsuite share price is up 30% to $5.70. Investors have been buying this cloud software platform provider's shares after it received and accepted a takeover offer. Dropsuite has entered into a scheme implementation deed with NinjaOne, under which it will be acquired for $5.90 per share in cash. The Dropsuite board unanimously recommends that shareholders vote in favour of the scheme. This is in the absence of a superior proposal and subject to an independent expert report. Non-Executive Chairman, Theo Hnarakis, said: "While the Board is highly confident in the long-term fundamentals and growth prospects of the Company, we believe the Scheme represents a compelling opportunity for shareholders to realise their investment in Dropsuite, for 100% cash at an attractive premium to where Dropsuite has historically traded."

Monadelphous Group Ltd (ASX: MND)

The Monadelphous share price is up 3.5% to $15.41. This may have been driven by a broker note out of Macquarie. According to the note, the broker has upgraded the engineering company's shares to an outperform rating with an improved price target of $15.93. Macquarie notes that the company's profit guidance for the first half was well ahead of its estimates thanks to better than expected margins.

Sigma Healthcare Ltd (ASX: SIG)

The Sigma Healthcare share price is up 8% to $2.92. This follows the release of a trading update for the Chemist Warehouse business. Sigma is aiming to merge with Chemist Warehouse next month. According to the release, Chemist Warehouse delivered a 13% increase in first half sales to $5,154 million and 36.1% jump in profit before tax to $436.8 million. The company opened 19 new stores in the half with two new stores opening in Dubai. It notes that this is "a new geography with attractive opportunities."

Telix Pharmaceuticals Ltd (ASX: TLX)

The Telix Pharmaceuticals share price is up 5.5% to $29.03. This morning, this radiopharmaceuticals company announced the completion of the acquisition of RLS (USA). It is the United States' only Joint Commission-accredited radiopharmacy network distributing PET, SPECT, and therapeutic radiopharmaceuticals. Management notes that the "acquisition immediately enhances Telix's presence in the United States, with a network of over 30 radiopharmacies dispensing radiopharmaceuticals manufactured by Telix and other companies."