May 28 (Reuters) - Several exchange operators on Tuesday

re-enabled routing to Members Exchange (MEMX) after disabling it

for a brief period.

MEMX Equities delayed the opening of its pre-market session

to 08:45 a.m. ET as the stock exchange encountered an issue. It

did not clarify what the issue was.

The exchange normally starts its pre-market trading session

at 7:00 a.m. ET, according to its website.

The New York Stock Exchange (NYSE), Cboe Global Markets and

Nasdaq were among the exchange operators that disabled routing

to Members Exchange during pre-market trading before resuming it

after a brief pause.

The issue also led to self-help declarations from the

NYSE and Cboe against Members Exchange. Both were revoked later.

A "self-help" is a notification issued by a trading

exchange when another exchange is dealing with internal problems

in processing trades and orders are routed through alternate

venues.

Nasdaq, NYSE and CBOE did not immediately respond to Reuters

requests for comment.