It means I found out something.

"may nalalaman ako" means "i know something". "i knew it/i found" out is "nalaman ko". "nalalaman" and "nalaman" come from the root word "alam" which means "to know." to a certain extent you can also relate both words to "laman" which among other things means "content."

What's the meaning of "may nalaman ako"? Does that mean "I've found it" or "I knew it"? may nalaman ako = I learned something May nalaman ako tungkol kay Sam. = I learned something about Sam. nakita ko na = I found/saw it Nakita ko na ang hinahanap ko. = I found/saw what I was looking for. I knew it then = Alam ko yun dati. I knew it, she's the guilty one. = Sabi ko na nga ba, siya ang may sala/kasalanan.