The bourse said more changes are expected in the composite index in April when it shifts to free-float market capitalisation as the basis for inclusion.
"After a rigorous review, we found out that the current index is already understated and no longer reflects true market movement," said Francis Lim, the stock exchange president.
The last time the bourse changed the composition of the main index was in 2001. The main index gained 2.39 percent on Wednesday to end at an 11-week high of 2007.12.
Banco de Oro Universal Bank, Manila Water Co, SM Investments Corp, Pilipino Telephone Corp (Piltel), and Philex Mining Corp were newly included in the index, the stock exchange said in a statement.
Piltel, up 6.9 percent on Wednesday, and Philex, 4.92 percent higher, had been dropped from the main index due to low trading liquidity.
Investor interest in Piltel has revived on an improved profit performance and the resolution of its debt problems.
Piltel, owned by number one telecoms firm Philippine Long Distance Telephone Corp, recorded net income of 4.6 billion pesos ($84 million) in the first half against 660 million pesos in the same 2004 period.
Trading activity in Philex, which owns a copper mine in northern Philippines, has climbed as interest in mining stocks surges after a Supreme Court ruling last year allowed foreign ownership of local mining firms.
Ginebra San Miguel Inc, Ionics Circuits Inc, JG Summit Holdings Inc, Music Semiconductors, and Philippine National Bank were dropped from the new index.
The bourse also said it will adopt revised sub-indices based on global industry classification standards set by Morgan Stanley Capital International and Standard & Poor's.
By December, the Philippine bourse will have six sub-indices from the current five, adding a new holding firms sector.