In afternoon trade, the S&P/ASX 200 Index (ASX: XJO) is on course to record a small gain. At the time of writing, the benchmark index is up 0.15% to 8,361.9 points.

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

ARB Corporation Ltd (ASX: ARB)

The ARB share price is up 2% to $30.80. This may have been driven by a broker note out of Ord Minnett this morning. Its analysts have reaffirmed their buy rating on the 4×4 auto parts company's shares with a trimmed price target of $37.00. While it has lowered its earnings estimates in response to near term challenges, it remains positive and sees plenty of value in its shares at current levels following weakness this year.

Block Inc (ASX: XYZ)

The Block share price is up almost 6% to $90.69. This follows a strong night of trade for the payments giant's shares on Wall Street. One leading broker that would be supportive of this buying is Morgan Stanley. A recent note reveals that its analysts have an overweight rating and US$67 price target on its NYSE-listed shares. This implies potential upside of approximately 15% over the next 12 months.

Mayne Pharma Group Ltd (ASX: MYX)

The Mayne Pharma share price is up 8% to $4.71. This pharmaceutical company's shares are rebounding on Friday after a brutal selloff this week. Investors have been rushing to the exits since the company revealed that its takeover deal could collapse. This has been driven by the receipt of a notice from Cosette Pharmaceuticals, alleging that a "Material Adverse Change" has occurred. This potentially gives its suitor the right to walk away from the $672 million takeover deal. Cosette cited a combination of issues as the basis for its claim. This includes Mayne Pharma's recent earnings update, ongoing litigation with TXMD, and an FDA letter.

Paladin Energy Ltd (ASX: PDN)

The Paladin Energy share price is up 7% to $5.79. Investors have been buying Paladin Energy and other ASX uranium shares today amid optimism that the industry could get a big boost from US President Donald Trump. According to Reuters, Trump is expected to sign executive orders on Friday that aim to jumpstart the nuclear energy industry. It said: "A draft summary of the orders said Trump will invoke the Cold War-era Defense Production Act to declare a national emergency over U.S. dependence on Russia and China for enriched uranium, nuclear fuel processing and advanced reactor inputs."