Traders often speak of the “January Effect” in the markets to describe a phenomenon that typically spurs a seasonal rally in certain types of shares. Investment banker Sidney Watchel first noticed this effect in 1942 but the phenomenon seems to be less pronounced as time goes by since markets are already primed for it.

As for factors that trigger this so-called January Effect, some say that it’s due to funds and traders reestablishing the positions that they’ve closed at the end of the previous year to crunch profits or for tax purposes. Others think that it’s due to the general sentiment that it’s best to start investing at the beginning of the year. Regardless these are the stocks that did well in January:

Alcoa (AA)

Approximate Shares Performance: 30% Up

Alcoa shares were up more than 30% for the month, building up from the company’s momentum since October last year when it spun off its value-added business Arconic. The company’s latest earnings report indicated that demand for aluminum continues to grow and that the price of the metal has seen an upside, possibly sustaining this for the rest of the year.

However, adjusted fourth-quarter profits, missed analysts’ estimates by a wide margin. Even so, revenue outpaced estimates at $2.38 billion and came in at $2.54 billion. The company was also able to offer full-year guidance of adjusted EBITDA (Earnings Before Interest Taxes) of as much as $2.3 billion, higher than analysts’ projections and twice as much as it made last year.

CSX (CSX)

Approximate Shares Performance: 32% Up

CSX corp shares are up approximately 32% for the month of January, thanks to a strong boost after the resignation of Canadian Pacific Railway CEO (Chief Executive Officer) Hunter Harrison and his decision to team up with former Pershing Square Capital Partner Paul Hilal to run CSX. The company’s shares surged 23% on this news. Harrison had acquired a reputation for turning around the fortunes of railroad companies, as he had done for Canadian Pacific Railway.