Firstly: 

We have already discussed the ruling on signing up with Bank al-Bilaad, in the answer to question no. 46588.
Secondly: 

From examining the funds system on the official website of the bank mentioned, the following becomes clear: 

1-The muraabih fund is based on investing deposited funds in commercial muraabahah operations which include buying different kinds of products – apart from gold and silver – then selling them for a higher price than the purchase price so as to earn a profit, in accordance with the rulings of Islamic sharee’ah.

2-The asaayil fund is based on investing money in stocks in Saudi companies, in accordance with the rulings of Islamic sharee’ah.

3-The sayf fund is based on investing money in selected Kuwaiti stocks in accordance with the shar’i guidelines.

Dr. Yoosuf al-Shubayli, a member of the bank’s watchdog committee, has stated that the asaayil and sayf funds which have to do with stocks do not involve investing money in companies that lend or give riba (interest), and that the muraabih funds has to do with trading in permissible merchandise on the basis of purchase with payment at a later date. 

End quote from the website of Dr. al-Shubayli. 

If the matter is as described, there is nothing wrong with investing in these funds. 

And Allaah knows best.