(This article originally appeared in The Trade)

Nasdaq is “assessing its options” following the Securities and Exchange Commission’s (SEC) decision to approve the Investors Exchange’s (IEX) application to become an exchange.

A spokesperson at Nasdaq told The Trade: “We are evaluating the SEC’s decision and assessing all options to ensure the best outcome for the US equity markets and all of its participants.”

The SEC officially approved the decision earlier this week following a controversial evaluation from US regulators.

In May this year, Nasdaq along with other trading giants, voiced its concerns over IEX becoming an exchange.

An acting attorney for Nasdaq wrote to the SEC threatening legal action against IEX over its use of ‘speed bumps’.

The speed bumps slow incoming orders by 350 microseconds to prevent high-frequency traders on its market from having any advantage over other participants.

Nasdaq wrote: “Commission lacks the authority to approve IEX’s pending application and to treat IEX’s intentionally delayed quotations as protected.”

It continued with a warning that “the proposed interpretation would be unlikely to survive judicial scrutiny.”

Market Maker Citadel said the IEX “encroaches on the traditional role of broker-dealers and would use inherent competitive advantages that exchanges have over broker-dealers.”

A recent report on the decision authored by TABB Group’s founder Larry Tabb, concluded the approval “presents a number of challenges.”

It said: “In no other market have regulators allowed an exchange to adopt a sophisticated time-altering and manipulative mechanism to their national exchange infrastructure and forced firms and exchanges to trade off phantom quotes.”

Chief executive officer at IEX Brad Katsuyama, wrote a letter following the SEC’s decision said: “We have faced several obstacles along the way and we learned along the way, but we hope our partners realise that our team’s hearts and minds are in the right place”