Donald Trump’s presidential election victory has increased the chances that President Barack Obama’s landmark net-neutrality rules could be rolled back, some telecom investors and experts said Wednesday.

The rules, adopted by the Federal Communications Commission in early 2015, marked a major victory for Silicon Valley companies, such as Alphabet Inc.’s Google unit. Aimed at ensuring a level playing field online, the net neutrality rules require broadband-access providers to treat all content coming across their networks equally,...