Today's move by the London exchange, however, raised speculation that all will come under pressure to change along the same lines.
The London exchange rejected the offer, but seemed to leave the door open for another.
The London exchange, for its part, had no official comment yesterday.
A spokesman for the London exchange said its board would meet soon to name a chief executive.
It may be several months before the future of the London exchange becomes clear.
Shares on the London exchange have been trading recently at about $1.80.
The London exchange is likely to make a decision about whether to join a global network within four weeks, he added.
How the bulk of these investors will vote on the London exchange is still not clear.
Nasdaq's offer values the entire London exchange at about $5.2 billion.
Nasdaq would also list its shares on the London exchange.
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